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Airtightness for new house

  • 05-11-2009 4:11pm
    #1
    Registered Users Posts: 153 ✭✭ liamolaighin


    Anyone know if all the new airtight membranes and tapes for walls and roof are worth the money. How much would you be lookin at for 3200 sq/ft house to tape all window and door openings & make roof airtight???

    Is this something all BER advisors are now recommending? I want to build a warm house, well insulated, but at same time keep my open fire. Not going passive so is output on membranes worth it or better spent on insulation. Thinking of pumping cavities...

    Are you inclined to believe tape and membranes are worth it 38 votes

    Yes
    0% 0 votes
    No
    100% 38 votes


«1

Comments

  • Registered Users Posts: 4,076 ✭✭✭ gman2k


    I would at the very least tape up the edges of window and door frames, to reduce uncontrolled ventilation/ heat losses.

    IMO this is worth it.


  • Subscribers Posts: 35,991 ✭✭✭✭ sydthebeat


    Anyone know if all the new airtight membranes and tapes for walls and roof are worth the money. How much would you be lookin at for 3200 sq/ft house to tape all window and door openings & make roof airtight???

    Is this something all BER advisors are now recommending? I want to build a warm house, well insulated, but at same time keep my open fire. Not going passive so is output on membranes worth it or better spent on insulation. Thinking of pumping cavities...

    the price depends on your build type.... block build wouldnt have as much need for tapes and membranes as a TF house would typically...

    im surprised that you would assume a BER advisor should be your first port of call. Your architect or architectural technician is the construction professional and should be advising you on these matters. The BER assessor may or may not be from a construction background so may not understand the implications of such specifications. If you are serious you should talk to your architect / technician about designing an air tightness scheme. The acceptable / accredited details are a good place to start but may not cover all the specific details that you require.


  • Registered Users Posts: 2,292 RKQ


    I agree with Syd.
    Airtightness is a requirement in the approved details. It will become an important part of future Building Control.

    IMO it is important and will save you money. Its an easy way to help future proof your build. Check out manufacturers web site for photographs of installation details etc.

    Simple logical steps will make a great difference - especially around the ends of floor joists in blockwork houses.

    Infra red cameras and blow door tests clearly show that airtightness works. I put it in my house 6 years ago!:)


  • Registered Users Posts: 2,573 ✭✭✭ mr_edge_to_you


    similiar query here - our builder has quoted us €1500 for "air-tightening" our house with a membrane sealer tape. he used more fancy terminology. He reckoned that the tape and materials would cost about €800 and that there would be about 2 or 3 days work for 2 lads.

    can i get peoples advice as to whether they think that it is money well spent? i'm not trying to build a passive house - from the start we've adopted a smart/sensible approach. A conscious decision not to lose to the run with insulation etc.

    any feedback would be much appreciated. we need to let him know before the plasterer arrives next week.

    thanks,

    edge.


  • Closed Accounts Posts: 5,433 ✭✭✭ sinnerboy


    similiar query here - our builder has quoted us €1500 for "air-tightening" our house with a membrane sealer tape. he used more fancy terminology. He reckoned that the tape and materials would cost about €800 and that there would be about 2 or 3 days work for 2 lads.

    Rough rule of thumb .
    1/3 Energy - you will lose through walls / floors/roofs / windows etc
    1/3 Energy - you will lose / consume on hot water . More if you have teenagers . Less if you don't
    1/3 Energy - you will lose through ventilation - intended and unintended

    It is worth investing in reducing this final part
    Is the cost reasonable - €12/m2 install price I would suggest as a budget .

    i'm not trying to build a passive house - from the start we've adopted a smart/sensible approach. A conscious decision not to lose to the run with insulation etc.

    I've watched over 25 years most clients and builders remark " the amount of insulation here is crazy" . And throughout that period progressively the min amount of insulation required by law his risen and risen over that period .

    It is set to rise further soon . 2010 regs will see for example a MIN u value for external wall of 0.21 ( currently 0.27 ) i.e. approx 25% tougher to achieve . But , but , but .... it does not end there . The maximum permissible calculated energy and CO2 emission rates will be set at such a level that U Values of 0.15 and even 0.12 may be required

    Or to put it in very simple terms - in 2010 - Passive House will become THE BASE LEVEL . I don't agree that you have " adopted a smart/sensible approach" . You are building the Automobile equivalent of what will soon be regarded as a Trabant - very out of date .

    .


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  • Registered Users Posts: 2,573 ✭✭✭ mr_edge_to_you


    Thanks sinnerboy! When i refer to smart and sensible i mean that we are trying very hard to keep our project on budget, doing okay - touch wood. Obviously there's no limit if you have the money! My biggest fear is running out of money, i'm very much a pessimist. Won't be happy until the last cheque is released. I'm an accountant so I need to know is that there is value in the 1500e.


  • Closed Accounts Posts: 5,433 ✭✭✭ sinnerboy


    I understand .

    There is an odd perversity in raising building standards ( or any standards for that matter ) during an economic decline . The fact is one is now building a soon to be outdated house . But there is a time value to money i.e if you HAVE the money now to invest in the future - you do so and if you don't , you cant .

    Sadly an unwelcome side affect of raising standards will be that fewer houses will be built

    I'm walking into grandmother/eggs territory now aren't I - you being an accountant :D

    All I would say is this . UK market research ( sorry I lost the link to it ) indicates that bathrooms and kitchens have a 15 year lifespan . If you are not committed to those orders yet - try to imagine all that bright shiny kit in a skip one day . You may then adjust you spending plans . If the other half lets you


  • Closed Accounts Posts: 102 ✭✭ restaurants


    gman2k wrote: »
    I would at the very least tape up the edges of window and door frames, to reduce uncontrolled ventilation/ heat losses.

    IMO this is worth it.
    Good idea. This is easy to do and well worth the effort.


  • Registered Users Posts: 1,137 ✭✭✭ holdfast


    A conscious decision not to lose to the run with insulation etc.
    Let go and break free from the accountant in you, this is one place you are going to get a payback you will have learnt that in college "payback period". just get a 42 inch lcd rather than 46 inch and half you heating and some of electricity bill aswell with a bit more insulation etc. Again make sure the guys doing the work have received training and tell them and get a air tightness test done it required by law and it will make them build the house right.


  • Registered Users Posts: 2,573 ✭✭✭ mr_edge_to_you


    Cheers guys, appreciate the feedback. I was close enough myself before hand but I'm trying to convince my OH that it is a few quid we won't regret.


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  • Registered Users Posts: 256 ✭✭ ninjaBob


    I would like to point out that you should be focusing on your bottom line. Putting in more insulation now, controlling your ventillation now and creating a good degree of airtightness now will save you money from day 1.

    Don't aim for some rating or stamp of approval from Energy assesors, builders, engineers or architects. Simply aim to do everything within your power to ensure once you move into your house that you are saving money. Do it once and do it right.

    Also be careful about Energy Assesors and others who give you information they may be mis-informed or simply talking out of their ass. As pointed out a good few of them simply don't have the background to comment.... like myself so I'll stop talking now.


  • Closed Accounts Posts: 5,433 ✭✭✭ sinnerboy


    ninjaBob wrote: »
    Don't aim for some rating or stamp of approval from Energy assesors, builders, engineers or architects. Simply aim to do everything within your power to ensure once you move into your house that you are saving money. Do it once and do it right.

    Also be careful about Energy Assesors and others who give you information they may be mis-informed or simply talking out of their ass. As pointed out a good few of them simply don't have the background to comment.... like myself so I'll stop talking now.

    Apart from ranting and possibly making your self feel better - what is actually useful here ninjaBob ? Think before you post - are you making a contribution ? (Rhetorical questions. )


  • Registered Users Posts: 1,137 ✭✭✭ holdfast


    Don't aim for some rating or stamp of approval from Energy assesors, builders, engineers or architects

    Ninjabob you seem happy enough to get help from energy assesors, engineers and architects judging from your passed post. maybe cause its free :rolleyes:


  • Registered Users Posts: 256 ✭✭ ninjaBob


    I was making two very simple points:

    Investing the money now when it's cheaper, will save you money in the long run.

    Not everyone has the background or experience in constructing houses, so don't simply construct the house to get a rating or meet the building regulations. Spend what you can to make a better house and save yourself money in the long run.

    Personally I thought they were valid points.


  • Moderators, Regional North West Moderators Posts: 43,176 Mod ✭✭✭✭ muffler


    ninjaBob wrote: »
    I was making two very simple points:

    Investing the money now when it's cheaper, will save you money in the long run.

    Not everyone has the background or experience in constructing houses, so don't simply construct the house to get a rating or meet the building regulations. Spend what you can to make a better house and save yourself money in the long run.

    Personally I thought they were valid points.
    Reasonable enough points to me.


  • Subscribers Posts: 35,991 ✭✭✭✭ sydthebeat


    ninjaBob wrote: »
    , so don't simply construct the house to get a rating or meet the building regulations.

    Your points may be valid, if mis-concepted.

    Building regulations compliance is a MINIMUM standard, not something to aim for and fall short due to budget!!

    'getting a rating' is something that is also legally required, it is not a luxury, its a necessity.

    Embarking out on a huge task such as building ones own home is a monumental task. It still exaspirates me how some people treat it with nonchalance.

    Having a goal or aim for this task is one of the primary factors in determining whether it will be a successful task or not. In these days of 'cutting cloth to measure' having a goal of projected running costs of the dwelling should not just be A factor, but in my opinion, THE most important factor in building. Whos to say what financial situation any of us will be in in 10 years time..... who would want a dwelling that costs 3-4 K a year to heat in these circumstances.


  • Registered Users Posts: 256 ✭✭ ninjaBob


    Sorry I should have clarified my points a little more clearly:

    One shouldn't aim to just meet the building regulations and leave it there, if their budget allows they should try and spend their money where they will achieve the greatest savings to their overall running costs.

    While a BER is legally required an A3 house on paper, may not perform like an A3 house.

    This is where the experience and knowledge of your engineers, architects etc will come into place.

    I used this document (which has been posted here a few times):

    http://www.planningportal.gov.uk/uploads/br/accredconbk.pdf

    It helped me pinpoint potential problem areas and keep and eye to ensure they were completed correctly.

    I personally didn't go with the AirTight Membranes (Block house with 135mm pumped cavity), but did seal around all windows, doors and services with tapes etc.. Given that I used Cozy boards on my external walls, I also ensured that my around my sockets were sealed to prevent any airflow behind the boards.


  • Subscribers Posts: 35,991 ✭✭✭✭ sydthebeat


    ninjaBob wrote: »

    One shouldn't aim to just meet the building regulations and leave it there, if their budget allows they should try and spend their money where they will achieve the greatest savings to their overall running costs.

    While a BER is legally required an A3 house on paper, may not perform like an A3 house.
    .

    sorry.,.. i misunderstood.

    i agree with these points completely


  • Moderators, Regional North West Moderators Posts: 43,176 Mod ✭✭✭✭ muffler


    Lay of the Smirnoff syd :D


  • Subscribers Posts: 35,991 ✭✭✭✭ sydthebeat


    muffler wrote: »
    Lay of the Smirnoff syd :D

    I'm more of a rum man myself!! :D


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  • Closed Accounts Posts: 5,433 ✭✭✭ sinnerboy


    ninjaBob wrote: »
    This is where the experience and knowledge of your engineers, architects etc will come into place. .

    Is an entirely different sentiment to
    ninjaBob wrote: »
    Don't aim for some rating or stamp of approval from Energy assesors, builders, engineers or architects.

    and
    ninjaBob wrote: »
    be careful about Energy Assesors and others who give you information they may be mis-informed or simply talking out of their ass

    Your initial post can be interpreted as advice to trust no one but yourself .

    Terrible advice . For most people the self built house is the biggest investment they will make . Good advice pays for itself many times over .

    You subsequent posts eventually indicate you believe this too .
    The matter may rest there as far as I am concerned .

    Make mine a Jemmy . Hic !

    .


  • Registered Users Posts: 1,137 ✭✭✭ holdfast


    I was wrong on jumping the gun on nijabob advice. Just a case of misunderstanding. I return to my stone to eat humble pie :(


  • Registered Users Posts: 256 ✭✭ ninjaBob


    Not all advice is good advice and bad advice can certainly cause alot of problems with your build.

    It's best to be objective about what advice you take onboard, but at the end of the day you are hiring professionals to do a job and that should also be factored in.


  • Subscribers Posts: 35,991 ✭✭✭✭ sydthebeat


    ninjaBob wrote: »
    Not all advice is good advice and bad advice can certainly cause alot of problems with your build.

    It's best to be objective about what advice you take onboard, but at the end of the day you are hiring professionals to do a job and that should also be factored in.

    if you do not trust the person giving the advice... DO NOT TAKE IT.

    Im not sure where you are going with all this. If you have had bad advise then fair enough, one bitten etc etc..... but your last few posts seem to throw architects engineers and energy assessors into a basket of professionals not to be listened to. That in itself is very bad advise.

    There are good and bad practitioners in all walks of life... its a good client who can seek out the good ones. The basis you use to seek out these good ones would be a factor in how successful you will be.


  • Registered Users Posts: 335 ✭✭ Naux


    ninjaBob wrote: »
    http://www.planningportal.gov.uk/uploads/br/accredconbk.pdf

    It helped me pinpoint potential problem areas and keep and eye to ensure they were completed correctly.

    I personally didn't go with the AirTight Membranes (Block house with 135mm pumped cavity), but did seal around all windows, doors and services with tapes etc.. Given that I used Cozy boards on my external walls, I also ensured that my around my sockets were sealed to prevent any airflow behind the boards.

    I have to agree with the sentiment here. I will be taking a similar view when building my house.

    The whole airtightness/hrv issue for me revolves around "the law of diminishing returns" The extra capital cost of getting the house virtually airtight to me is not likely to be worth it. Obviously some people want to bring the airtightness etc to the highest standards and fair play to them I say. I would also say however that this approach is not for everyone.


    I live in a semi-detached house at the moment(built 2002, basic insulation etc) and I find the house warm. I wonder how I'll cope with living in my new house next year!!


  • Closed Accounts Posts: 5,433 ✭✭✭ sinnerboy


    Do you know what level of air tightness you need to achieve to comply with building regulations ?

    What is your advisor telling you - on the back of a DEAP calculation ?

    Air tightness is a part-component making up total energy losses as I posted earlier ( post 6 ) . So you can't assess air tightness in isolation .


  • Registered Users Posts: 2,573 ✭✭✭ mr_edge_to_you


    decision made. we're going to go with the air tightness. spoken to a few engineers i know and along with all your advice we've decided to go the air tightness membrane.

    thanks to you all for your advice! as always, much appreciated.


  • Registered Users Posts: 1,137 ✭✭✭ holdfast


    Naux it’s not as simple as that, the saving made up having the right airtightness can bring big savings. The difference between passing and getting a best practice result on the test can save you 30 %. Moreover when you are sitting down in front of the telly with herself and she says I feel a draft around my ankles and the fire is roasting:eek:. Or if you go the other way and the house is too air tight for the planned ventilation you end up with mould, condensation and sick build syndrome

    This can even happen no matter how well the house is insulated. Houses are built and ever trade will punch holes in the construction. Any house can be warm when you have put enough heat in it. The test of new house is how little heat or no heat is required. You will also need to have an airtightenss to know if the house has been build to standard. It’s a great way of ensuring the house is build well, think of it as stamp of approval on the work and the money you invested in the house.


  • Registered Users Posts: 2,489 No6


    I kind of missed this post but having read through it (quickly) no one seems to have picked up the op's decision to have an open fire. As far as I am concerend airtight houses do not work with open fires, he should at least consider a solid fuel room stove. There is little or no point in spending thousands on airtight membranes and then having a big hole in the sitting room!!


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  • Registered Users Posts: 335 ✭✭ Naux


    No6 wrote: »
    I kind of missed this post but having read through it (quickly) no one seems to have picked up the op's decision to have an open fire. As far as I am concerend airtight houses do not work with open fires, he should at least consider a solid fuel room stove. There is little or no point in spending thousands on airtight membranes and then having a big hole in the sitting room!!

    Agreed. I missed the open fire line myself.


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