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    Hello to everyone!

    Like many others I have been regularly visiting here as a guest user in search of inspiration, information and explanation, but as my build plans gain momentum the time has come to join the community and get involved.

    My wife and I are hoping to build a 1.5 storey home of around 335sqm with a traditional vernacular farmhouse appearance and an ambition of finding the sweet spot between capital outlay and low energy bills/ good comfort levels.

    We're at the Building Control stage at the moment so my arrival here is in many ways to sound out ideas in a bid to make them work cohesively as a cost effective package. While I admire and draw inspiration from the Passive House principles, PHPP was not our starting point and as time has gone on I am realising the rules of diminishing returns can be applied to many decisions the would be self builder faces. This has been a tough pill to swallow in some ways as both my wife and myself are only children who like our things to be perfect!

    We've had the pleasure of meeting Seamus from Viking House and as well as pricing us a timber package he showed us a recently built home primarily heated by a large solar collector.

    Well that seems like plenty of rambling for now, time to explore the full realms of the forum as a paid member!
    • CommentAuthorTriassic
    • CommentTimeOct 3rd 2013 edited
    Posted By: slidersx200traditional vernacular farmhouse
    So what does this look like in your neck of the woods?
    The Planning Service produce a Design Guide for Rural NI that explains in quite some detail what is desirable, but a brief summary of our design would be a linear 3 room cottage with adjoining stone outbuilding (which is our kitchen) and hopefully the impression that the house has evolved over time with two rear extensions, making it more of a T shape. With quite a high wall plate level, a limited palette and simple lines (no projections at eaves etc.) overall it has a fairly austere appearance.

    Although far from ideal in terms of the area of external walls, our design is basically one room deep throughout. I personally feel this results in more pleasing proportions and combined with the high solid to void ratio, circa 38 degree roof pitch and vertical emphasis to external openings on paper at least satisfies most of the recommendations in the Guide.

    We managed to push the envelope of our Outline Planning Permission slightly which stated the house should be "of single storey construction" but had no ridge height restriction. We ended up at around 6.5m ridge height, no dormers, just roof lights and gable windows and seemingly in Planning terms this is still seen as single storey.
    After some resizing hopefully I can get the renderings to display correctly:smile:
    • CommentAuthorslidersx200
    • CommentTimeOct 3rd 2013 edited
    Rear, we made some amendments since this was done though:
    Garage/ Mancave!
    A flat roof?!!
    You seem to be on the right track slider.

    As you have indicated your external wall to interior space ratio is going to present a challenge in terms of heat loss.

    It also looks from your images that getting sufficient insulation into your sloping roof will be another challenge if you don't want to compromise your 1st floor room sizes, likewise the proportions of the flat roofed area will make it difficult to get a low u-value on the roof and keep a decent ceiling height. It will probably mean that you will have to use a phenolic insulation in these areas but personally I don't like the stuff.

    What's your orientation like? Is the total heated space of the house 335sqm or does that include the garage?

    Whilst Seamus has had success in building solar enhanced passive houses I think that the size, proportion and location of your house will probably present a very big challenge in covering the heat load with solar.

    Assuming the front of your house is south facing a quick estimate from PVGIS would suggest that you will be around 1000-1500kWhrs short of covering your heating load with solar (although I'm probably taking a leap and making too many assumptions but I'm guessing a heat load of around 800-1000kWhrs per month in Nov, Dec, Jan, Feb.) and another 900kWhrs or so for DHW during the winter months. What heat source are you proposing to use to make up the difference?
    Good morning and thank you for the comments!

    The flat roof area has a fall of around 3 degrees and will have a standing seam zinc finish, hopefully resulting in something similar to the attached photograph. This area originally contained the pantry and boot room but after some tweaks we moved the boot room closer to the outbuildings and made space for a formal dining area outside the kitchen which opens to a paved area at the rear through French doors.

    The first floor has an internal span of 5.3m and height at the eaves is just over 1.3m. This assumes 100mm PIR over 150mm rafter filled with spray foam insulation and a 50mm service cavity. The flat roof has a similar construction except for the covering. The energy consultant I spoke to says this build up gives an airtight warm roof that is "easy to do right" and claims a U value of 0.12. The SAP report suggests the average to be more like 0.14, but this may(?!) be due to a different (brand) spray foam being used in his calculations.

    I have some reservations about this approach and one alternative I'm looking into is the possibility of using a glulam ridge beam with timber I joists sheeted top and bottom with something like OSB and pumped with silver/ platinum beads. I have received one quote for the beams and joists so far but don't have enough information to know whether this would be cost effective or even work as a system. It would probably sacrifice about 50mm headroom if we keep the service cavity but I believe the U value would be closer to 0.1.

    The front of the house faces SW and it is the house only that is 335sqm. The outbuildings deliberately face directly South so that we could fit PV at a later date if we choose, but heating is likely to be from a heat pump. Due to the rocky nature of the site a GSHP may require bore holes making ASHP more economically viable.

    The house Seamus showed us had a similar orientation and while without question I found the solar heating impressive, the potential grants etc we could qualify for in the North would probably make the heat pumps more attractive financially.
    Slider I have just finished a low energy build and whilst not focused on getting PHI certification I found that getting a PHPP done for the house really helped me in being able to quantify what improvements were cost effective and also for sizing the heating system. I'm not familiar with the SAP calculations so don't know how the level of detail compares.

    Similar to your approach I had the house designed according to passive house principles, airtight and with minimal cold bridges but didn't get hung up on trying to achieve the target heat load of 15kWhr/m2/a.

    If you are not going to heat the house via the ventilation system and are going to install a heat source such as an ASHP then I believe it is of little relevance if your heat load is 15kWhr/m2/a or 25, the impact of the running costs will be very small, once you are down to low numbers is what really counts.

    I could for example have specified a better MVHR unit than the one I went for but the payback on the upgrade was about 25 years so not worth it IMO. To get to PHI certification would have meant a big extra spend on windows with something like a 100 year payback so I took the practical approach and settled for the best return for the money.

    The PHPP results really helped me in coming to those decisions so whilst it cost quite a bit, it saved me from spending a lot of money needlessly.

    BTW it's a nice part of the world you are in, when I was younger I made a lot of memorable trips up that way to Kirkistown.
    The SAP report is quite a jumble of numbers to me too and the present version seems to include some provisional figures so while there are pieces of information that may be useful, not all of it can be accurate. The various measurements do seem quite comprehensive though and suggest they account for orientation, overshading and thermal bridging.

    It suggests the annual energy cost would be £1899 which at about 17p/unit equates to roughly 11170 units. If I understand the calculation, dividing 11170 by the area of the house means the energy requirement is approx 33.35kWhr/m2/a.

    I believe this figure includes hot water and lighting (both of these are mentioned in the report at some stage) and think some of the provisional values will be rather unkind to the predicted results (such as Air Permeability at 50 pascals as 10.00). Apparently the fact we are including MHRV is quite detrimental to the "score" as it uses electric and we would currently be rated as C73 for Energy Efficiency Rating and C76 for Environmental Impact Rating. Given the lengths I think we are going to this is rather disappointing, but I have been assured the "As Built" report will make better reading and that the assessment isn't very accurate for low energy type homes.

    Another item that will no doubt affect the score is our potential window choice, a topic that my wife and I seem to deliberate endlessly and usually results in me searching the internet for hours in search of the mythical beast... an efficient, airtight sliding sash!

    As previously mentioned, our design is rather plain and we feel it will fall upon using the correct finishes such as the roof slates, render finish, the stonework, the rainwater goods and definitely the windows to show the traditional character we are trying to achieve. To both our minds the only acceptable aesthetic for the windows is the sliding sash, not only due to the style of the house but also the shape of the openings.

    There are offerings out there with A ratings but these are usually PVCu and when I mention to suppliers they are for a low energy house they usually suck air through their teeth and say "you don't want to do that, they'll be rattling and drafty in no time". This hardly inspires confidence when it comes from the people trying to make a sale!

    Another common thing I seem to hear from window suppliers is that triple glazing (in sash windows at least) isn't worth the expense and that gasses like krypton will have leaked after 10 years reducing the performance to below that of double glazing. Add to the confusion that they say some windows can be A rated when double glazed but drop to a B when triple glazed as solar gain and the level of light that pass through are also measured and the whole thing has my head in a spin!

    In truth, with having MHRV it is perhaps going to be a rare occasion that the windows will be open so the actual way they open isn't of the utmost importance. I have started looking into mock sash windows and while there are options available that tick the appearance box, many seem to only accept a 24mm glazing unit and are fairly basic in their draft proofing.

    Alternatively, there are products that seem to perform exactly how we want in terms of insulation and air tightness but invariably fall short in the looks department. The two characteristics that seem hard (should read so far impossible!) to find in an efficient window are getting the sight lines in the glazing to match up vertically between top and bottom pane and that the top pane should sit proud from the bottom by an amount that gives the correct impression of depth. Many mock sash windows have a wider glazed area in the lower pane and a rather flat appearance, especially if they are advertised as storm proof.

    If you managed to follow all that and haven't fallen asleep I'd really love to hear any suggestions anyone may have for potential window suppliers. I appreciate care should be exercised when recommending or shaming businesses on the forum so please feel free to whisper if that is preferable:)
    • CommentAuthorPugliese
    • CommentTimeOct 4th 2013
    We have 3g sash and also had the TF built by Viking. Windows excellent but can't say the same about the TF erection. PM email if you want to know more.
    • CommentAuthorGaryB
    • CommentTimeOct 6th 2013

    Welcome to the Forum from another Norn Iron member!

    Your house definitely has a rural NI vernacular character. Are you in the Mourne conservation area, by any chance? The house looks very similar to a number of vernacular restorations we were involved a few years back for the Mourne Heritage Trust.

    BTW, you need to get a new SAP assessor. There is a complete disconnect between the description of the house and its servicing and the SAP output figures. It looks like default SAP values have been used all over the place.
    • CommentAuthorslidersx200
    • CommentTimeOct 6th 2013 edited
    Hi Gary

    Thank you for your kind comments. The site is in Saintfield, not far from Downpatrick. What fulfills the guidelines in rural design doesn't always lend itself to energy efficiency such as being one room deep so we have worked hard and accepted many compromises in an attempt to marry the two. A simple box would no doubt have been cheaper to build and have lower fabric losses but we see opportunity in the spaces we have created to inject quirkiness and character that four straight walls just can't offer.

    I'm sure it won't be to everyone's taste and Kevin McCloud would no doubt see it as a pastiche but I believe that embracing the traditional rather than the contemporary should result in a home that is timeless rather than dated if done right.

    Re the SAP assessor, I did ask them for some amendments and to explain how the results might be affected by other potential changes but didn't push too strenuously as it satisfies building control requirements and I see it as a low estimate or worst case scenario.

    To put the annual energy cost in context, our current home is a 200sqm 1980s bungalow with double glazing, an 11 year old oil boiler and 300mm loft insulation. Our appliances are mostly A rated or better and I have installed low energy light fittings wherever possible. We use around 2500ltrs of oil and 5000 electric units a year which at today's prices I estimate at just under £2kpa. As I see it, to potentially run a 335sqm house (that I like lol!) For similar money seems OK and if the actual running cost is lower that's a great bonus.

    If we come in on budget the build cost for the new house is about the same as the current value of where we live now but i'm not counting my chickens as we have expensive taste:wink:
    • CommentAuthorGaryB
    • CommentTimeOct 6th 2013

    Agreed that at this stage the actual SAP value is not critically important as it meets the Building Regs, except that you may be making decisions on the basis of inaccurate life cycle costs.

    You will need to have an accurate EPC however as it may affect the resale value of the house and the amount of future rates payable.
    • CommentTimeOct 7th 2013 edited
    Posted By: slidersx200Although far from ideal in terms of the area of external walls
    You'd make a significant improvement by giving the flat roofed bit a lower-pitched 'cat slide' roof - wd cover up quite a lot of lossy external wall with negligible increase in roof surface - effectively made the insulated volume more cubic. Also far cheaper and less troublesome, easier to build/detail, than zinc.

    Anyway, instead of zinc, what's wrong with basic (thicker galv, colour coated grade) corrugated iron? Nothing cheaper, v reliable. One from the internet
    • CommentTimeOct 7th 2013 edited
    Mine and an0ew, recently completed in Bristol
    • CommentAuthorslidersx200
    • CommentTimeOct 7th 2013 edited
    Gary, I believe the as built sap report will be much more accurate and is relevant to your points on resale, rates etc. I did ask for a few changes but as I have been the squeaky wheel quite often with my architect I'm picking my battles so to speak as I want to maintain a good working relationship with him.

    Tom, thanks for the suggestion! I think though as our garage has a tin roof and we may add a round top barn assuming we're not broke and disheartened by the end of the process I would steer clear of corrugated materials on the house as I want the distinction between dwelling and outbuilding.

    The way I'm looking at it is that the downstairs spaces will have underfloor heating so will be fine with u value of 0.15 and upstairs has maybe 60% wall area compared to downstairs, the other 40% effectively being roof which should have a u value of around 0.12 all being well (I'm reviewing the details at the moment to see if this can be improved further). The 3 bedrooms upstairs all have provision (space) for an en suite shower room and there is also a family bathroom. I think an electric towel rail with thermostat in each of these should take care of most of the heat demand. This plumbing arrangement probably sounds excessive but we have talked of running a b&b when we retire so are trying to plan ahead.
    • CommentAuthorArchmoco
    • CommentTimeMar 31st 2014 edited

    How have you got on? My view would be triple glazing is a must. If companies are telling you go double it's because they don't do triple! A lot of companies are also doing deals for free upgrade to triple. Our new build has large quantities of glazing south and west and the passive solar is great, with minimal heat lost. We original wanted a aluclad timber but the budget only stretched to aluclad pvc.

    Regarding energy efficiently ensure you have as airtight as you can and go with heat recovery, it's a great job. We have underfloor heating through fed from a 1000Ltr accumulator tank, heated by solar and wood burning stove, it works but I'm trying to iron out some issues to make it more efficient.

    Best of luck with the build.
    Just at the tendering stage now and hope to have all prices in within the next week or two.

    I managed to find a Scottish window manufacturer that will supply hardwood sliding sash windows with up to 44mm glazing units and a very comprehensive draft proofing setup and a local firm that will supply PVC with 28mm units and krypton fill for about £5k less. Although PVC, the frames have mechanical butt joints and run through horns so are at the better end of the aesthetic scale lol!

    If the budget will stretch I hope to go the hardwood route, but it will all depend how the other items stack up. My only reservation is about the potential weakness in airtightness of wooden French doors although the Scottish company said they could look into adding a double rebate and additional draft strip.

    Heating quotes are my new headache as half the quotes I'm getting say "based on the heated floor area we recommend...." with no consideration given to the actual U values and airtightness targets. Whether lazy, stupid or trying to fleece me for the top of the line heat pump, my money won't end up in their pocket!
    • CommentAuthorMackers
    • CommentTimeMar 31st 2014
    Love to hear what company are doing the sash windows so I can have a look. Might know of a company here in Northern Ireland that can do it, I've seen first hand the fantastic job they did of restoring old sash windows but unsure if they will make new ones.
    I have no affiliation with them, other than so far receiving excellent customer service, but the Scottish company is called Baird's Windows. My main point of contact there is Malcolm, one of the directors and I gladly tip my hat to a top bloke:-) He was prepared to give me the information on their glass packets such as g value and light transmittance and calculate U values for each opening.

    I'm making a point to stop by when I take the mountain bike to Scotland next month to check out their products in person.
    • CommentAuthorMackers
    • CommentTimeApr 1st 2014
    I actually looked up the website of the company I came across and I must say I`m even more impressed. Their a local firm if you want their details I can give them to you?
    That'd be great! I'm waiting on prices coming back from two companies I spoke to at self build show. They called me a while after the show and have had the drawings for around three weeks now, so I'll make one chase up phone call tomorrow then place in the bin if nothing comes back promptly.
    • CommentAuthorArchmoco
    • CommentTimeApr 1st 2014

    If you have any queries let me know I'm just down the road, I'm just finishing a self build. My window are very modern but I'll check my supplier to see if they do anything more traditional
    O see if they do something

    • CommentAuthorArchmoco
    • CommentTimeApr 1st 2014

    Google internorm and look at their ambiente range. The local supplier would be Fenecosystems in Coleraine. I originally wanted their wooden frame with an aluclad exterior, and pvc aluclad for the wet rooms, the wood and pvc are identical in profile and I could mix and match, but for cost settled for pvc aluclad throughout, and I have not regretted it. Their windows are excellent and Fenecosystems are very good

    • CommentAuthorMackers
    • CommentTimeApr 1st 2014
    Check out Dask timber.They have a very good website saw their conservation work repairing sash windows on a job I did and was impressed. Some nice details on their website.
    Thanks archmoco,

    I'm almost embarrassed to go on their stand at the shows as I first spoke to one of their reps when we were at Outline stage (over 3 years ago!) and seem to end up chatting at every event, but never get down to asking for a quote. Think his name is Paul and he's very easy to talk to.

    I don't question the quality of the windows, in fact you'd probably be hard pushed to beat it, but none of the profiles are in keeping with the style we're aiming to achieve. I'd definitely consider them for a different project, but the pen might shake a bit writing the cheque!
    Cheers mackers,

    Must be a good product, I think every house in their photos is a Des Ewing design, which also may imply they're rather pricy! Might give them a ring anyway.

    Heron Joinery have a very comprehensive range, but the guy I spoke to on the phone was another false promiser who failed to get back to me, so that went in the bin!
    • CommentAuthorMackers
    • CommentTimeApr 2nd 2014
    You get what you pay for. You want your windows to last as long as your house. But if they budget doesn`t stretch you need an alternative. I`m surprised so many companys don`t get back to you, I thought they would be crying out for work.

    Who is this Des Ewing fella?
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