Posted By: Mike GeorgeAnd this example applies to all software.

So basically all software is bunkum and all we can safely do is what our grandfathers did for evermore?

Somehow, we manage to design new aircraft and even land spacecraft on flying rocks. And sure, sometimes they crash instead.

But all I was doing was pointing out that you'd made much too broad a claim for the limitations of software modelling. I seem to have provoked an even broader set of claims (strawmen, even) instead. IMHO, there's some truth (quite a lot, actually) in what you're saying but you've pushed your argument much too far.

I agree - it's as if there is a notion that building regs are a nonsense and to be ignored. If you plan on taking this insulation - which let's remember has been ripped out because it has caused issues with dampness elsewhere - and stick it under your floor which is designed to be ventilated then you are taking risks, don't believe otherwise. It isn't an approved method, and with the number of cavity wall installers out there and the big business it has become, don't you think that they will have been looking at ways to expand their operations? If filling solums with beads was that clever an idea they would have been filling them long ago and getting their grant monies.

If you want to do it the sensible, safe, trusted & approved way - you take up the timber flooring, hardcore & blind the surface, fit your polystrene (in sheets), DPM & concrete. That is the correct way to do it.

Posted By: willie.macleodI agree - it's as if there is a notion that building regs are a nonsense and to be ignored. If you plan on taking this insulation - which let's remember has been ripped out because it has caused issues with dampness elsewhere - and stick it under your floor which is designed to be ventilated then you are taking risks, don't believe otherwise. It isn't an approved method, and with the number of cavity wall installers out there and the big business it has become, don't you think that they will have been looking at ways to expand their operations? If filling solums with beads was that clever an idea they would have been filling them long ago and getting their grant monies.

If you want to do it the sensible, safe, trusted & approved way - you take up the timber flooring, hardcore & blind the surface, fit your polystrene (in sheets), DPM & concrete. That is the correct way to do it.

Hallelujah. Common sense prevails

Posted By: djhSo basically all software is bunkum and all we can safely do is what our grandfathers did for evermore?

Now I didn't say that did I..

Posted By: djhSomehow, we manage to design new aircraft and even land spacecraft on flying rocks. And sure, sometimes they crash instead.

Indeed, but not really a fair analogy that.

Posted By: djhBut all I was doing was pointing out that you'd made much too broad a claim for the limitations of software modelling.

Well it didn't come across that way. It seemed you were completely disagreeing with what I'd said. My apologies

Posted By: djhI seem to have provoked an even broader set of claims (strawmen, even)

Not at all regarding what you have said, though we do seem to have misunderstood the meaning of each others points/comments

Posted By: djhIMHO, there's some truth (quite a lot, actually) in what you're saying but you've pushed your argument much too far.

Thank you. A way forward seems to be for us to discuss in what way you think I have pushed it too far?

Posted By: willie.macleodI agree - it's as if there is a notion that building regs are a nonsense and to be ignored.

I think a very important point that often gets overlooked is just what the regulations are. The regulations state requirements, not solutions, and to the best of my knowledge they are sensible (there might be the odd bit that's silly but livable with). And the regulations are the minimum that you are legally required to do.

But most of the stuff that causes disagreements is in the Approved Documents and associated 'standards'. They are NOT legally binding*, they just provide a way to conform to the regulations that doesn't involve extra effort. You're free to do it another way as long as you do whatever it takes to convince your BCO its OK. The Approved Documents and associated documents are written by lots of people, many of whom have commercial agendas, and in consequence there are what I regard as some quite silly bits in them and lots of places that seem to be disguised attempts to try to restrain trade.

But I just built a load bearing straw bale house and I expect I'll be getting a completion certificate quite soon. You won't find that in the Approved Documents. That's a good aspect of our building control system; if I want to risk my money on an unapproved technique, I can, as long as a structural engineer signs it off as meeting regs. If I lived in Germany or Austria, I wouldn't be able to - they're not allowed to build load bearing straw bale, because it isn't mentioned in their codes either, and the codes are prescriptive.

So it's quite right to warn people that new or unapproved techniques can be dangerous and expensive and suggest that people only try them with their eyes wide open, but at the end of the day there's nothing wrong with using an unapproved technique if you want to and if you set about it in the right way.

The issues for big firms are quite different and to them, approval means a lot more.

* Some of the standards have separate legislation to support them that do make them legally binding, such as the Wiring Regs. And some of those are sensible.

Posted By: djhI think a very important point that often gets overlooked is just what the regulations are. The regulations state requirements, not solutions,

Not sure about that, they do provide both requirements and solutions (by reference to other tiers of documents); just not the only ones as you say.

Posted By: djhBut most of the stuff that causes disagreements is in the Approved Documents and associated 'standards'. They are NOT legally binding*, they just provide a way to conform to the regulations that doesn't involve extra effort.

Well sort of, they are not legally binding in themselves, but the 1984 Building Act is. And it is the Act which endorses the Building Regulations and Associated Approved Documents (and yet further tiers such as my linked document above)as *A* means of compliance with the Law.

Posted By: djhYou're free to do it another way as long as you do whatever it takes to convince your BCO its OK.

Again sort of, I think that's a bit simplistic. What is supposed to happen is that the Building Inspector can/ will authorize alternatively (Third Party Certified) methods. (Note this is where possible - Straw Bale being a tad complex for that) Alternatively they may accept the endorsement of a particular design or method by a suitably qualified person - such as an appropriately qualified Architect or Structural Engineer.

So in practice a BBA or sometimes a (less onerous to get) CE Mark will gain you compliance; and sometimes you will need Professional endorsement (Note such professionals carry PI Insurance backing up their specifications).

Where it goes wrong for me is that Building Inspectors have the power to relax requirements; and furthermore they cannot be held accountable personally for their decisions... good or bad (unless this has changed recently) . This because each and every Inspector acts @on behalf of the Secretary of State)

An example of mass relaxation of a requirement in the past is the controversial use of multifoils....But generally it doesn't happen to that level. And in my experience relaxation of a particular requirement generally happens when there are conflicts with other regulations. Or when there are sound technical reasons for doing so.

I've not ever seen ventilation requirements relaxed, though I have seen plenty ignored without the Building Inspectors knowledge. And i've seen the consequences :(

And as far as I can see no-one here is suggesting that filling sub-floor voids with polystyrene beads has any form of Certification whatsoever. And neither does it have the formal (or even informal) endorsement of a qualified Architect.. (And I have asked several times if any Architect posting here is willing to formally endorse it and put their PI on the line......

So anyone thinking of doing this. be aware that you have absolutely zero recourse if it all goes pear shaped

Posted By: Mike GeorgeI have asked several times if any Architect posting here is willing to formally endorse it and put their PI on the line

I don't think an architect is qualified to judge the merits of such as system; it would rather be a suitably qualified engineer. And I expect that the terms of both an architect's and an engineer's PI means that they would first have to be employed to express such an opinion, which is obviously much easier in the specific circumstances of a particular case.

Chemical injection of a DPC causing rotten wall plates, cement pointing to Victorian houses, Who is picking up the liabilities for these inappropriate actions?

Look, just crack on and do it if you want, but there is absolutely no similarity between beads underfloor and in a cavity wall. Can't say you haven't been warned.

For a start, you have a timber structure in the floor. Completely different temp/humidity conditions as well.

And guess what? No bead filling company in the world is stupid enough to put beads in a timber frame house with a cavity & masonry outer leaf. Because the risk is too high that the timber will rot.

So having read all this I'd like to know what ways there are to well insulate a suspended timber floor without the risk of incurring problems. Historically it seems to be a building element that relied upon draughts and high heat loss to keep it dry and rot free. Is it even compatible with modern energy efficiency standards?

Posted By: Nick ParsonsIt's those unscrupulous make-up salesmen again!

Reds under the Bed

Posted By: EasyBuilderSo having read all this I'd like to know what ways there are to well insulate a suspended timber floor without the risk of incurring problems. Historically it seems to be a building element that relied upon draughts and high heat loss to keep it dry and rot free. Is it even compatible with modern energy efficiency standards?

Posted By: Nick ParsonsI don't think there is a way without running the *risk* of problems. I have been involved with hundreds of under-floor insulation jobs, of which probably less than a handful have had any problems (to my knowledge - I acknowledge that I do not visit the ones I was involved with 30 years ago!)

Tips to maximise the chance of problem-free and successful include:

- Always draught-proof the perimeters before insulating.

- Ensure there is adequate *cross*-ventilation.

- Ensure that ventilation entering at joist level is ducted so that it enters the void *below* the final insulation layer.


I have found that quilt between joists with breathable membrane below - all joints and perimeters taped - seems to work well. I have sometimes had issues where I have used Pu to stuff the gap between the last joist and the cold cellar wall - where quilt wold 'suck' - with condensation on the Pu and being transferred to the joist. With regret (as I don't like un-insulated bits) I have sometimes removed the infill at this point.

*I have started a new thread so that this does not hi-jack the poly bead thread*

'Best practice for under-floor insulation?'

I'd agree 100% with that if the wooden floor has to remain. My preference though is to completely remove all timbers and put in a load bearing concrete slab

But Mike, Willie - is concrete slab a safe option in a terrace situation or will moisture be driven elsewhere - i.e. into party walls.

Actually I've shown in over 50 houses that there isn't a risk when you fill the void beneath a suspended timber floor with EPS beads, and its absolutely the best solution economically and performance wise. There's no difference between pumping the floor with Light Weight Aggregate or EPS beads only that EPS is a better insulator and is cheaper. I've done all types of houses, some with external insulation, many without.
I tested the humidity and temperature of the joists and if anything the environment at the joist end in the wall has improved.
I'll even go to say that when you insulate large areas of a house the heat loss is focused at the junctions and the temperature of these junctions increases, my neighbours house had a rising damp issue that was solved by pumping the beads, heat drives moisture out!

When I externally insulated my first house 15 years ago there was no details available in the building regs, so I would also have been called a cowboy builder by Mike back then, now he's externally insulating his first house and suddenly he's the resident expert.
It was the same with our Passive Slab foundation system 10 years ago when we were building our first one, now there's over 1,000 completed with a zero failure rate and orders are doubling every year.

An Irish Company Airpacks/Kore who produce EPS Bonded bead have decided to apply for an IAB or BBA cert for pumping the void beneath the floors and the cavity in timber frame houses with EPS beads. Checkmate Insurance who are very forward thinking and have a lot of experience with alternative construction methods, they did their risk analysis and said they will supply the back-up insurance. So its moving ahead, you never know in a few years it may be part of the building regs.

Posted By: Viking House
An Irish Company Airpacks/Kore who produce EPS Bonded bead have decided to apply for an IAB or BBA cert for pumping the void beneath the floors and the cavity in timber frame houses with EPS beads. Checkmate Insurance who are very forward thinking and have a lot of experience with alternative construction methods, they did their risk analysis and said they will supply the back-up insurance. So its moving ahead, you never know in a few years it may be part of the building regs.

Having seen the disaster that filling "safe" masonry cavities with beads can be - good luck to any insurance company that decides that they want to take that risk when it comes to turning timber frames to mush it will get very, very expensive. Early timber frames which will be the ones people want to insulate are generally cheaply built to low standards - no decent vapour barriers, no cavity left for ventilation, what a recipe. The CIGA already pays out enough simply removing the stuff, the cost of replacing rotten sole plates etc will be horrendous, are we all forgetting this used insulation that we are talking about in this very post was no doubt installed by a CIGA company, and had a BBA cert?!

Living in an area which sees extreme driving rain may be clouding my judgement - some of this stuff may be ok in the south of England. But just because it can work in a sheltered town house doesn't mean it will be OK everywhere. I look forward to seeing what happens with their testing.