Tue, 01 Sep 2026 22:41:15 +0100 https://www.greenbuildingforum.co.uk/newforum/ Lussumo Vanilla 1.0.3 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18341 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18341 Mon, 01 Sep 2025 15:58:30 +0100 BWork
Greenbuilding.co.uk, owned by the AECB, promotes excellence in design and construction. This website, including the very popular Green Building Forum, was set up by Keith Hall, who co-founded the AECB back in 1989. Keith kindly donated the site to the AECB on his retirement in 2025.

The Greenbuilding site is for everyone from industry professionals including architects, builders, developers to green enthusiasts and homeowners looking for information and a place to discuss all aspects of sustainable building.

With the money that we hope to raise from this Crowdfunder we will be able to update the original website and forum, currently working using older technology that does not allow for necessary changes to the platform. With your support of a much-needed funding boost we will be able to invest in new technology that will bring the site into the 2020s. This will make it easier for visitors to navigate around the site and read the valuable information and resources we share, for those on their sustainable building journey. Users will also be able to sign up quicker and get involved in the conversations.

https://www.crowdfunder.co.uk/p/qr/dyR52gZn?utm_campaign=sharemodal&utm_medium=referral&utm_source=shortlink]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=289 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=289 Tue, 15 May 2007 18:00:44 +0100 GBP-Keith https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18471 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18471 Fri, 28 Aug 2026 17:11:51 +0100 Doubting_Thomas
Since it's on everyone's minds right now, we've been discussing how we can use less water at home. One idea is using cold bath water to top up our WC cistern.

Ours is a concealed cistern (Geberit Duofix) so the proper access is via a removable faceplate. The idea with this would be to introduce a separate hole and hose arrangement on one side, with some sort of inlet valve to allow topping up the water level using a watering can or jug filled from the bath.

Any suggestions for what we could use at the filling end? All I can think of is some sort of wall-mounted tundish like the below.

Also, is this mad? Anything we should be wary of, other than probably needing to de-scale/clean the cistern more frequently?]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18465 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18465 Fri, 07 Aug 2026 15:32:33 +0100 Rex
Have a 6000 liter rainwater collection tank in the garden (mainly for toilet flushing but also garden use) and it has of course, been empty for the past two months.

Wish I had installed an even larger tank but 15 years ago, who could predict this extended drought.

So at the behest of SWMBO, I am investigating most likely, one (or perhaps two) IBC and how to fill. Obviously, the best location is somewhere that I can divert rainwater but the design of the house is such that the only place would be against a side wall and these are somewhat ugly things.

Since the loft tank (for flushing) is filled by a submersible timer pump, I could access the pipe and T off to an IBC situated in a less obnoxious location. But is it possible to install a ball valve in an IBC so that when fill, it does not overflow?

I have not researched this idea but thoughts would be welcome.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18470 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18470 Wed, 26 Aug 2026 13:32:37 +0100 Rex Thought I had a separate CAT6 thread but only topics relating to my attempts, namely toilet seat and plasterboard.

Knowing that y'all are sitting on the edge of your seats, after a lot of procrastination and alternative plans, plus attempting limited demolition (Right said Fred, gotta take the wall down!), persistence has paid off and yesterday, I found the fish rod end and have finally have the CAT6 cable form the loft (second floor), horizontally through the Posi-joist / Warmcell floor/ceiling and into the wardrobe. From there , it will be a simple vertical drop to where I will install the CAT6 socket.

Don't recall any job where I have been so persistent in my efforts.

I won't make good until the fibre to the house is installed and I know the CAT6 is working; then a simple decoration job.

I did not remove the toilet but did remove the small cabinet beside the toilet which allowed me to bore another 100mm hole into the 22mm OSB to get a better angle.

Appreciate all the advice and suggestions.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18453 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18453 Sat, 04 Jul 2026 14:48:15 +0100 Rex

Frequently happening as I get older, I am getting my knickers in a twist as technology leaves me behind.
At the moment, broadband and landline is with PlusNet via fibre to the pole. We are not paying for the landline, but it does receive incoming and we would pay per minute for outgoing calls.

My contract is ending but PlusNet are no longer offer a landline, just Full Fibre b/b. However, their associate company EE, will offer full fibre to the house and I assume, VoIP to keep the phone and phone number.

I am told that an engineer will have to assess how to get the fibre to, and then, into the house. At the moment, it is overhead to the front roof apex, then phone cable to the various RJ45 sockets which was part of the building process. The ''customer help' was not exactly helpful with my questions, but ......

Fibre has to come to the router which if it was in the loft, can I then use the existing wiring to the computers on the g/f?

The 'unhelpful' assistant was suggesting the fibre will have to be routed down the wall then drilled through the wall to where the office is located. The house is timber frame with Warmcel insulation. There is the breather paper on the frame (but that is inside the cavity) and internally, there is scrim under the Fermacel. Drilling through either of these materials is like drilling into a ball of wool; it just rips everything to shreds.

How does a fibre cable come into a very well sealed house if it has to be drilled through the frame and insulation? Once inside the house, can I use the existing wiring to use additional computers in different rooms?

Thanks and toodle pip]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18469 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18469 Tue, 25 Aug 2026 16:01:56 +0100 Doubting_Thomas
It feels sensible to pour a level hard standing here as a base for all of the above. My current thought is a concrete raft slab of 100-150mm thickness would be more than enough support, but I'm open to suggestions on this.

Three sides are enclosed by ~2m high concrete retaining walls supporting neighbour's gardens, so formwork along the remaining edge should be straightforward.

My questions are:

- Should I insulate and/or damp proof below it, anticipating the potential ultimate use as an outdoor room? Or are these generally raised up on pedestals anyway?

- Will I need reinforcement and or movement/expansion joints in this footprint?

- Anything missing? Ducting for electrics perhaps?

I realise this could spiral into a full-on house slab if I'm not careful, and I'm keen to keep things simple and affordable. More likely than not it will remain a concrete extension of the patio for many years - I just don't want to miss an opportunity for some future-proofing.

NB - I can't dig down much deeper for the risk of upsetting the retaining walls, so underground nuclear bunkers aren't going to happen!]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18467 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18467 Thu, 20 Aug 2026 11:33:40 +0100 thebeacon
I’m seeking some advice on making good the pathway at the front of my house. Its currently a 50-100mm slab of concrete which has some cracks and a drain in. The water currently runs towards and pools in front of the door.

I would like to repair the footpath and add a slight ramping in front of the door to direct the water to run away from the house. The entire path is about 2.6 x 1.3m. I imagine some areas would need 40mm while others less than 10mm.

I’d rather not break out the entire slab and add a resin based concrete product on top. Does anyone have any experience or advice with doing this? I have been looking at Cretex® EP Mortar (https://polycote.com/contact/) as a possible option to use.

Thanks,
Tom]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18443 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18443 Thu, 11 Jun 2026 11:42:34 +0100 fostertom
1. The new thinking, which removes high-standard External Wall Insulation (EWI) from its pedestal as the default/ideal for retrofit, on grounds that the embodied carbon (i.e. the CO2 and CO2-equivalent released to atmosphere) created in 'quarrying', manufacturing, transporting and installing EWI, is likely to exceed, sooner and for longer duration, the in-use carbon it saves over the building's subsequent lifetime.
Couple that with the rapidly declining carbon content of mains electricity, which means that electricity consumed over the building's in-use lifetime, already and increasingly carries little penalty in global heating.
Then, compared to super-insulation hence consuming minimal energy-in-use, the alternative of omitting the super-insulation hence consuming plenty of 'harmless' electric (via heat pump) energy-in-use, can actually be a lot better for planetary climate, both in this emergency-short-term, and over the building's lifetime.

2. Retrofitting the 30% of UK building stock which is still-uninsulated cavity wall, with or without EWI the cavities should be filled (CWI), as it's near-impossible to prevent outside air blowing around in the cavity. Even fitting EWI can't be relied on to seal the multiple cracks, entry points and open-to-loft top of typical cavities - outside air is still liable to bypass the EWI, separated from the interior only by the inner skin. External render can't be relied on either. Even Partial-fill CWI is poor at preventing outside air blowing around in the cavity; it really needs to be full-fill CWI.

3. CWI is cheap to install, with small embodied carbon. So, considering both 1. and 2. above, the new default looks like installing full-fill CWI, without EWI, along with electric (via heat pump) energy-in-use. In which the CWI is an indispensable part, hardly works without.

4. But what about cavity-wall buildings in high-exposure areas? There, CWI is pretty much banned by Building Regs, certainly with traditional 50 wide cavities (as opposed to more recent 100-ish cavities) and certainly in exposure Zone 4 areas (i.e. most of the west/southwest of UK). External render doesn't help.
https://assets.publishing.service.gov.uk/media/606c366ad3bf7f400e10af54/wic-final-report.pdf also gives little hope that a coat of gunk would make the wall more suitable for CWI.
Does anyone know different?

5. Without CWI, a house has nearly zero insulation, if outside air is blowing about only separated from the interior by the inner skin - even if accepting plenty of 'harmless' electric (via heat pump) use. Especially if extending an unfilled cavity-wall house; the existing cavity wall becomes an internal wall, but super-cooled because its cavity is continuous with the still-external parts of the cavity wall adjacent.

6. Similar applies if you've EWI'd your half of a semi-detached house; your unfilled cavity, inside the EWI, will be super-cooled because continuous with next-door's unfilled cavity.

So WTF to do about all this? Any solutions, bright ideas?]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18466 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18466 Sun, 16 Aug 2026 17:16:07 +0100 Rex
The headline on the front of today's Telegraph is what can only be described as 'surge pricing' for water during droughts. The aim is to encourage us to use less water.

This really anger me as we have a 6k liter rainwater collection tank and apart fro the fact that I'm not paying for incoming and by default, sewerage charges for using that water, I am unlikely to get any consideration for the fact that I am using less treated water than most houses.

With all the building regs we have in place, surely it makes sense that every new build, whether single houses or estates, must have a large rainwater collection to be used for toilet flushing. After all, every new build has to have a large soak-away, so why not collect that water before it goes to the soak-away?

It is absolute madness to flush expensively treated, potable water down the lavatory.

Now I'm off my soapbox!!]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18440 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18440 Thu, 28 May 2026 20:27:00 +0100 Rex
Just seen this on the Mail on Line web site.

https://www.dailymail.com/news/article-15854881/solar-panels-explode-home-explodes-flames-family-inside-escape.html

Will we ever hear why this happened? Bet the estate developers will have a nightmare with all the other owners wanting reassurance their solar panels will not catch fire. There is a 100 Taylor Wimpey built estate near me and they all have solar panels.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18457 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18457 Tue, 21 Jul 2026 19:02:37 +0100 Rex
In my continuing quest to find a way to thread a CAT6 cable from the loft to the office, it may (only may?) be useful to remove the toilet to allow better access to the small area of floor below the pipe.

Not a big job, just a couple of screws and wiggle it free from the fittings. Of course, I would have ensured the cistern is empty.

But the toilet has been in place for around 15 years and I am wondering if the various seals should be replaced when re-installing, or are they all OK to reuse? Of particular concern would be the two yellow seals, which I assume are not replaceable. I would give a smear of silicone grease around the seal before reinstalling.

Your thoughts most gratefully taken on board.

Thanks]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18461 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18461 Wed, 29 Jul 2026 13:53:50 +0100 Rex
Me again!!!

I frequently feel that design somehow does not improve the function, and this is exactly the case.

As in the two photos below, I have one of these bath tap shower fittings. In the lower photo, push the right thing and it switches from bath filling to shower. But!!!!

Frequently, either this does not happen or if it does, the design malfunctions and upon turning the water off, it will not revert to bath or most frequently, supplies both shower and bath at the same time.

The left spring sits in a recess in the body of the tap, so should all be locked in place. Disassembly usually shows one of two things: 1/ The spring has somehow, become dislodged or 2/ one of the O rings has been forced by water pressure from its seat. The water is running at 3 bar because that is the recommended pressure for the softener.

How to resolve the all to frequent dismantling beats me. It happens pretty much every couple of months. I have investigated replacing the tap unit, but want the same, which of course is either no longer available or is surplus stock for around a very profitable £250.

Having dismantled, reset whatever is unset, reassembled, it will work as it should for a few months, then the cycle repeats itself.

Grateful for any insight into how to ensure the push button works every time as it should.

Thanks and toodle pip]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18463 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18463 Thu, 30 Jul 2026 16:47:39 +0100 tony
https://share.icloud.com/photos/053drZp42Ur_dTRWMN-hRQb8w

Hope the link works]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18459 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18459 Mon, 27 Jul 2026 07:25:39 +0100 Rex
Continuing with a different topic but still related to my CAT6 cable saga, I think I am planning to cut at least one hole, and maybe two 10 cms holes into the plasterboard ceiling.

My wife wiggled the fish rod (oven sized earth wire) and I can clearly hear that it is kinda where I want it, but nevertheless, still around 10 cms+ away from where I can grab hold. The option is to drill an access hole ito the plasterboard ceiling, behind which is the Warmcel!!!

On the destination side, it is not a major issue as we have emptied the wardrobe and the dust can fall onto the shelf. But the office side (which is where the wire is at the moment, has all the office equipment below.

Apart from removing, disconnecting everything, dust sheets, etc, is there a way to drill a hole in plasterboard that does not send dust everywhere? I've seen vids on a small, drill-bit hole but not 10cms. Of course, I would use a vac but that is challenging with 10 cms. Perhaps a padsaw?

Your thoughts appreciated.

Thanks

Rex]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18460 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18460 Tue, 28 Jul 2026 11:17:41 +0100 WillInAberdeen
I put breathable wood-fibre IWI with Lime Green Solo plaster on the external stone wall of a room, and want to hang plain lining paper (no vinyl) to match the existing finish on the other internal walls. I will paint the lining paper with some breathable paint, probably Earthborn.

Lime Green say they don't recommend wallpapering their plaster but didn't explain why.


ISTM that lime plaster walls have traditionally been wallpapered for 100s of years including in my house, so not sure what the issues might come up?]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18051 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18051 Fri, 15 Dec 2023 09:32:39 +0000 djh https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18458 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18458 Thu, 23 Jul 2026 18:04:13 +0100 DrewWiley
On the inside Its open oak rafters, then oak square edge sarking with 3mm spacing using random sized boards. I dont want any insulation on the inside of the building as it looks lovely inside.

Externally i dont want any soffits or fascias just open rafters and perlin ends.

My dilema is insulating the roof, my initial thought is as follows

the sarking is pretty flat however not perfectly flat.

Rafters are 80mm so on top of the sarking lay a vapour membrane (i need to this to be black as i will see it through the sarking gaps inside) ill then screw using stainless spax washer heads a 80mm wide, 50mm deep oak battens on top of the rafters (externally). i will then use kingspan 50mm k107 in between each of these new battens (from the ridge to the end of roof). then my normal roofing approach counter batten with draping roofshield followed by pantiles. Would this be a suitable approach?

I would need to use an oak batten running the length of the roof that is 50mm tall to stop the insulation sliding down and providing a more decorative finish.

This all sounds like a mix between warm and cold.

Any suggestions would be welcome, i did look into TLX Gold etc but wasn't keen.


Or do i simply use something like Solitex Fronta Quattro, then PIR, then counter battens then tiles.


Thanks]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18452 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18452 Fri, 03 Jul 2026 00:04:36 +0100 Victorianeco https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18446 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18446 Mon, 15 Jun 2026 12:07:43 +0100 Charli
I've got 30K and want a comfortable house with the lowest bills. Happy to DIY almost anything, I'm capable and practical and find it all fascinating.

With a south facing-roof solar pv is worthwhile, can fit 4.2kWp of panels on the roof and there's adjacent south-facing land that I could fit more on. I think that 6kW of panels with excess going to heat dhw will give me largely free hot water for most of the year.

Insulation would be next on my list. 400mm loft insulation is easy.
Garage I'd do a flat or pitched roof with 150mm pir in, and some form of roof lantern/velux. And IWI. The garage has no direct heating and that’s fine.

Need new windows on the north side- pvc triple glazing. The lack of condensation on the windows ever is worth it.

EWI would need the roof extending, the wires moving on the front and I've no idea what to do with the gennel (internally the narrow stairs are there). Would rockwool and lime render play nicely with the 'old houses are always damp' line I keep reading? XPS below dpc? I've no idea how far down the house goes yet- there's unlikely to be much in the way of foundations.
IWI would mean no thermal mass (wfh so in the house all day everyday largely), the kitchen/bathroom would have to wait until those rooms needed some work (I don't want to rip out a perfectly good bathroom for a few years). And the rooms are already tiny- but I could sacrifice enough for 50mm pir. Which is better than nothing, but not inspirational. (Still no idea what to do on the stairs-wall).


Any ideas/inspirational stories/words of warning/things I should go and think/read about?
Many thanks.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18450 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18450 Tue, 30 Jun 2026 09:59:42 +0100 fostertom
I need to get up to speed with the varied considerations, like we've gradually learned with wet systems, UFH, ASHP etc. Not least grant aid. Aware of the horrors of 70s/80s cheapo air-heating, and duct-routing issues. And DHW.

Any pointers?]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18449 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18449 Sun, 28 Jun 2026 13:44:21 +0100 Rex
There was a recent article in the newspaper regarding the a/c numbers in different countries. Japan (my wife is Japanese) has around 91% domestic a/c installations, the UK, less than 5%.

My wife is really, really keen to get an a/c in our house. 3g, 180mm of Warmcel insulation; I don't think it is going to happen as I'm not drilling large holes through the glazing or walls. She even thanks we could replace one of the 'smaller' glazing panels to accommodate the a/c pipe. No way Jose!!!

Her further research finds this kind of unit: https://nessally.co.uk/ Apparently, according to her, they are very popular and very good. My feeling is, it is all marking hype and a money making scam.

Is there any 'new' technology that makes these portable a/c units as good as the blurb suggests? Are they generally any good or essentially, just an expensive fan that will be in the skip in a few years time?

Grateful for your thoughts and opinions.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18447 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18447 Tue, 16 Jun 2026 12:03:45 +0100 borpin
https://www.telegraph.co.uk/gift/c79c96400f3a8bff
https://www.telegraph.co.uk/money/net-zero/i-spent-900000-creating-the-ultimate-eco-home/

One thing I noted is that he is funneling his MVHR extract into a 'cupboard' around the Heatpump. That sounds like an excellent idea.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18435 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18435 Wed, 13 May 2026 08:29:03 +0100 ChrisGT Cavity walls with 80mm glass wool batts, clod roof, dot and dab plasterboard walls and a terrible airtightness test
Planning to:

Fill cavities below dpc with ecobead.
Create warm roof by increasing rafter depth with intello membrane on inside and blown in gutex or warmcel and solitex plus counterbattens and battens above.

150mm eps from 300mm above ground to foundation fixed to exterior brick walls. Timber frame made from 2 x 50x50mm timber with noggins to create 150mm cavity to be filled with gutex and 40mm rendered woodfibre board outside. Intello against bricks connecting to foundation and roof vapour control layer.

Does this sound like a good plan. Have considered parge coat in wall or passivpurple but intello seems cheaper and more eco.

Triple glazed windows hung outside current wall in picture frame.

Any suggestions or thoughts on improvements?]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18441 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18441 Wed, 03 Jun 2026 20:41:28 +0100 Victorianeco
Looking for my own interest more than anything?

Any tips or thoughts?]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18439 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18439 Tue, 26 May 2026 16:23:27 +0100 Brightonreno21 We live in Brighton and have a Victorian terrace which is south facing and high on a hill so tends to take a bit of a battering from rain and wind. A lot of the houses on our road suffer with damp in rooms at the front

On moving in, we noticed active damp in a master room at the front of the house. The opinions we got at the time where either very expensive damp proof materials (chemical injections etc), or we were offered the suggestion of using tanking slurry to waterproof the wall. This has effectively worked, that room is now dry.

We are now doing a Reno and having read much more about breathability we’ve started to worry about this. We are wondering if we get the render done in breathable lime render, could we keep the wall as it is (remove the tanking will also be damaging for it we understand)

We’d welcome views on how much of an issue it would be to have one room be tanked/not breathable - if we then get the render done breathably.

Whilst we are reluctant to invasively remove the tanking we don’t want to be storing up too many problems]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18428 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18428 Tue, 05 May 2026 18:28:24 +0100 Rex
While cleaning today, I found in the dark recess of a cupboard that is effectively, our plant room (HW cylinder and boiler cupboard) a pile of soft stuff; no idea what it is but vacuumed it. Thought it may have been coming from some insulation around the top of the wall hanging boiler.

Checked again just now, and at the back of the cupboard on the floor, I see ants. They appear to be coming from a very small hole where the Fermacell and screed meet.

I don't like eradicating insects but I also don't want ants nesting in the timber frame / Warmcell. Google tells me how to prevent them coming into the house but what is the best way to eradicate them from where I cannot see?

Thanks]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18429 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18429 Tue, 05 May 2026 20:28:22 +0100 Victorianeco
Specifically, I would like to compare:

1. Cavity Fill Only: Filling the cavity with 80mm expanded polystyrene (EPS) graphite beads while keeping new windows (3G) within the traditional layer.
2. Cavity Fill plus External Wall Insulation (EWI): Performing the above and adding a 120mm EPS board external layer.

While the latter is more thermally efficient, it is also more labour and material intensive. I need to evaluate the payback period based on current material costs and research.

Furthermore, I have concerns regarding the impact of the 120mm EWI on the property's interior. Extending the wall thickness may reduce natural light and affect viewing angles from within the room, particularly at the 30 to 45-degree angles we currently enjoy. There is also the potential loss of the window frame's aesthetic "framing" effect to consider.

What are your current thoughts on these two approaches based on up-to-date material costs and thermal performance research? Please let me know if there are any other factors I should consider at this stage.

Thanks]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18432 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18432 Mon, 11 May 2026 21:04:47 +0100 chrisinbrighton It appears to last way longer than sealed units and a lot better performance.
My only concerns are how visual the small spacer dots are and the width of the packer.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18424 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18424 Fri, 17 Apr 2026 19:53:40 +0100 chrisinbrighton My own experience of aluminium on bikes is that it can go brittle with age.

Thanks]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18433 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18433 Tue, 12 May 2026 08:21:32 +0100 thebeacon
While digging in the front garden recently I found a capped old concrete/clay pipe that leads back to the main soil drain.

My question, was this once a soil vent pipe? And if it was should I reinstate it? We had to lower the garden in front of the house, so now it sticks out the ground. I either want to cut the pipe to lower it and recap it or fit a soil vent pipe if it’s required. Other houses in the area have what appears to be a vent in their front gardens.

Cheers,]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18427 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18427 Mon, 04 May 2026 19:31:46 +0100 Rex
Neighbour has gone on holiday and asked me to keep an eye on their house, including giving some liquid refreshment to some plants.

Looking up from the rear garden yesterday, this is what I see. Went to check from the balcony and the glazing is presumably, toughened glass but also laminated. It is only the inner pane that has fractured. Wheat could possible be the cause?

Toodle pip]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18425 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18425 Sun, 19 Apr 2026 23:00:46 +0100 ChrisGT https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18421 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18421 Sat, 11 Apr 2026 11:40:30 +0100 minisaurus
Has anyone experience of them? The positives are many, but what are the negatives? price I guess]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18423 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18423 Wed, 15 Apr 2026 10:35:53 +0100 andyman99
Whilst starting to help my son renovate his bathroom we came across a rather unpleasant problem. The tiles on an external wall pretty much fell off and everything behind is very wet.
Construction: this “front” wall appears to be a simple timber frame structure. From outside to in: PVC cladding - roofing felt (what I would call old style felt not a breathable membrane) - timber frame filled with fibreglass type insulation - plasterboard. The water ingress does appear to have come from the inside. The timber structure is very wet, the insulation a sodden mess and the roofing felt disintegrates as you touch it. We have an insurance assessment this Friday but I would like to understand a way forward if possible before then. I think the main structural walls are brick, left and right whilst front and back appear to be this timber frame structure. 2 rooms across the front, bathroom and bedroom. No obvious signs of a problem in the bedroom front wall. I’m wondering how fixing this would best be approached? Any ideas welcomed]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18361 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18361 Tue, 07 Oct 2025 12:20:39 +0100 Nick Parsons
I'm just raising this in a new thread since I am not sure where it goes from here. I have a 'soft spot' for GBF, and was 'in' long enough ago not to have paid anything, but if we assume (I don't *know*) that the number of active users ('supporters') is relatively small I am not at all sure how the £6500 will be raised. I'd be sad to see it go, but maybe that has to be??

Just some random ramblings, but any other thoughts would be useful to users and, I am sure to AECB as new 'Guardians of GBF'.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18414 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18414 Thu, 12 Mar 2026 08:19:49 +0000 fostertom https://www.greenregister.org.uk/civicrm/?civiwp=CiviCRM&q=civicrm%2Fmailing%2Fview&reset=1&id=5840&cid=40824&cs=f4a98d878cf7eb7a71342f57279ea33e_1773283838_720

"... research into stone structures to help move their use back into everyday construction.

Standing three storeys tall, the Stone Demonstrator shows stone’s potential as a contemporary, low-carbon, structural material.

Natural stone offers a route to cut carbon emissions sharply. Compared with a conventional reinforced concrete frame, the Stone Demonstrator drops embodied carbon by roughly 70%, and by around 90% when set against steel.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18419 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18419 Fri, 10 Apr 2026 07:20:37 +0100 Victorianeco
Any suggestions on materials that give a good corporate image but also boast good green credentials.

They must all be standardised and suitable for standing desks

TIA]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17796 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17796 Sun, 26 Mar 2023 23:01:59 +0100 zak99
We need to replace our broken concrete driveway and also provide a separate hardstanding for parking/working on a vehicle etc

Other than the usual concrete, block paving, slabs, gravel are there any other lowish impact surfaces I may not be aware of please?

Permaculture garden designer suggested gravel and sleepers for the drive or gravel with random planting in the gravel but she is hard to nail down on the details. Like will a wheelie bin or wheel barrow pull through the gravel or how do I do low nutrient random planting with type 1 sub base or will the sleepers be slippery in winter. My wife would like to break up the gravel expanse with some sparse slabs but designer feels gravel will always end up on top of slabs.

For the hard standing beside the garage I may possibly be able to reuse some old slabs but wondered if there are other lowish impact materials for a new surface?

Whats your experience please?]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17406 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17406 Sat, 05 Mar 2022 20:47:49 +0000 chrisinbrighton
The walls are all 700mm thick stone and one of these walls is covered in slate with a 50mm gap. I was thinking this would be a good place to add insulation.Is there a particular type which would be best and does a vertical slate wall need a breathable membrane?
Thanks.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18415 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18415 Mon, 16 Mar 2026 11:29:31 +0000 ChrisinYorkshire
Hopefully this makes sense – if its hard to follow let me know and I’ll look at posting a diagram.

I would like any thoughts about my planned action for insulating a wall where my house transitions from being underground to above ground.

Context
The house is built against a valley side. It is mostly of traditional thick sandstone construction, although 30-40 years ago or so some areas were rebuilt with cavity walls.

To one side of the house two floors are effectively underground – the top floor pokes above ground approximately at floor level. The wall against the earth has been fitted with a cavity drainage system, metal studs, with PIR insulation and careful attention to airtightness/VCL.

My current area of concern – the transition point of said wall, as it pokes out from the ground. This involves 3 large wooden beams that are bedded into the wall (upon which sit the top floor floor-joists). I am switching to breathable insulation for the top floor room (a kitchen).


Further context and observations

It has been a very wet winter, the kitchen is unheated and has no mechanical ventilation. Where one of the beams enters the wall I am getting a 23% moisture reading ( this is the top face of the beam)

Floorboards have been cut away (approx. 70-80mm) from the wall during summer last year. They are reading 20% moisture at the edge closest to the wall, this is in the coldest corner of the room.

A floor joist running along side the wall, but separated with DPM and a gap, is reading 21% moisture.

Therefore I think there is a general humidity/condensation issue, though the beams bedded into the wall might also be wicking some moisture from the wall.
The coldest corner of the room, is a bit damp, also from condensation I believe. Note this corner is going to be behind kitchen cabinets.



Current course of action:
- I have dubbed out and parged the wall with NHL 3.5 and sand mix.
- Planning to meet the PIR insulation with wood fibre board which will then continue up the wall.
- I have considered but don’t want to use an eps/xps plinth layer at the transition from PIR to wood fibre boards, because I don’t want to trap condensation/moisture around the large beams that enter the wall.
- There is a leaky gutter externally that will be repaired/replaced.
- Kitchen will have mechanical ventilation and heating installed.

Any concerns over ‘wet process’ vs ‘dry process’ wood fibre boards? Wet process appear to be more capillary active than dry process boards. Frustratingly it's hard to find suppliers of wet process boards in tongue and groove.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18416 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18416 Tue, 24 Mar 2026 11:40:09 +0000 fostertom https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18379 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18379 Thu, 04 Dec 2025 16:25:55 +0000 revor https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18413 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18413 Mon, 09 Mar 2026 20:04:02 +0000 Gareth J
I didn't ask him, but what's the advantage over a non breathable setup? Something like DPM, concrete slab, PIR/EPS, top layer/s. His place is all above ground and is a well built house.

I can see that there are likely lower carbon and non plastic based advantages but from a performance perspective, does the floor need to breath? Is it mitigating potential moisture issues? This might have been covered loads or be completely obvious and I've missed it so apologies in advance!

The suspensoended floor in my own solid wall cottage needs attention at some point in the future so am keeping half an eye on options. It's complicated by being half dug into the ground around it though.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18408 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18408 Sun, 22 Feb 2026 19:05:31 +0000 Victorianeco
Considering roofing options to replace 70 year old concrete tiles.

Solar makes perfect sense at this point and so does a standing seam roof.

This could be a good all in one system?]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18410 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18410 Sun, 01 Mar 2026 10:27:23 +0000 Rex
We own a maisonette that is rented out. An old Potterton Kingfisher cast iron boiler, bullet proof, always passes the annual test but by today's standards, very inefficient, provides the DHW and heating.

The gas guy always recommends replacing with an electric boiler. My wife sees the Fischer Future Heating (https://fischerfutureheat.com/product/electric-boiler/) ads in the weekend papers and is keen for me to investigate (advertising pays!)

I don't know one end of a replacement electric boiler for the other; the Trustpilot reviews are all great, but they are mostly based upon installation in the past few months, not long term usage. Are these boilers any good? Apart from boosting the EPC rating and a small saving on the annual test, are they worth the installation expense?

Thanks and toodle pip]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18391 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18391 Tue, 06 Jan 2026 12:45:55 +0000 fostertom Thickness - 15, 12, or will 10 ply be adequate?
Material - WBP ply? - any concerns about poss long-term intersitial condensation, positioned as they are well outboard in the insulation/sandwich? Is fibre-cement or other mineral board used instead? I guess interstitial condensation is no more likely than on/in the the window frame itself, but with less drying potential?
Assuming air-sealing to the wall, and to the window frame, are do-able, what about air-sealing the four corner-edges of the box?]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18407 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18407 Sat, 21 Feb 2026 21:37:47 +0000 Victorianeco
While I can appreciate it's quicker and lighter we feel we would possibly like vertical cladding.

I guess that would mean we'd need vertical battens followed by horizontal followed by the cladding...

What are the pros and cons of each? And are there any simpler methods of fixing vertical boards while ensuring drainage?]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18406 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18406 Tue, 17 Feb 2026 17:03:54 +0000 Rex
My slab is reinforced poured concrete sitting an industrial corrugated galvanized metal base with an air gap below.

When I park the car following a wet drive, inevitably, water drips onto the concrete and there is frequently a puddle in the morning. It is probably not of concern to me, but it does cross my mind that reinforced concrete with water sitting on top can in time, cause the rebar to rust with the obvious consequences.

Is this something I should be concerned about? Alternatively is there anything I can apply / paint on the surface to reduce the absorption of water?

the mats at the front are to 'contain' water from the front arches, but the large damp patch is from water that I guess is dripping for the various under-body panels.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18398 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18398 Fri, 23 Jan 2026 07:59:39 +0000 Rex
Kinda trivial as it does not concern me but just out of interest!

Have a new neighbour in a 1930's house and they are having the place re-wired. Obviously, it mean removing all the wiring that is covered with plaster.

Which gets me thinking, how would a future owner of my t/f house with Warmcel insulation, do the rewiring?
Not easy as they would have to cut slots out of Fermacel. I also have the ceiling fully insulated with Warmcel.

How is it done?]]>