Adam2 Posted January 3, 2022 Share Posted January 3, 2022 We've got our roof on and have windows being installed later this month - the installation includes air-tightness tape inside + outside so am expecting this to be pretty effective. House is ICF and we've applied tape around roof connections to walls - hope/anticipate that the main the walls/floor junctions will be fine. Trouble is that we have 3 doors inc the main entrance area (2m x 2.6m) areas that we won't have installed for some months yet but I'd like to see how the air-tightness is shaping up before we put up the plasterboard and if we have issue we can try and resolve while it's relatively accessible. Is it feasible to do this type of testing when our windows are in but with doors missing? At the moment we have OSB over door openings - would it be sufficient to apply air-tightness tape around these or is OSB air permeable? Any idea on cost for this kind of testing? - am in Dorset Link to comment Share on other sites More sharing options...
JohnMo Posted January 3, 2022 Share Posted January 3, 2022 Should give you a good idea of where you have issues. Our pre test cost £200 and it was a negative pressure test only, you can easily feel any leaks especially when it's cold outside. Link to comment Share on other sites More sharing options...
Iceverge Posted January 4, 2022 Share Posted January 4, 2022 6 hours ago, Adam2 said: Is it feasible to do this type of testing when our windows are in but with doors missing? At the moment we have OSB over door openings - would it be sufficient to apply air-tightness tape around these or is OSB air permeable? Yes if you tape the OSB in place correctly. 18mm OSB is generally considered airtight however I reckon 11mm is too if it is a well made board. Don't bother getting a professional to do a trial. Rather buy something the car fan below. Bigger is better. Then screw and tape it into one of your sheets of OSB. Get some crocodile clips and wire and attach to your car battery. They develop a howling gale compared to a proper blowerdoor. It makes it easy to find leaks and you can do so without time pressure. You should be able to just reverse the polarity to change fan direction if needed. Listen for the biggest leaks. Lick the back of your hand and feel for the smaller ones. Use a lighted candle and ram it into a length of conduit or tape it to a broom for a hyper sensitive leak finder. 2 Link to comment Share on other sites More sharing options...
Adam2 Posted January 4, 2022 Author Share Posted January 4, 2022 Cheers @Iceverge I think that will be a bit of fun after windows are in ? Link to comment Share on other sites More sharing options...
ProDave Posted January 4, 2022 Share Posted January 4, 2022 Another vote for a DIY blower door. I made mine out of a substantial sheet of cardboard, lots of tape and an old office desk fan as the blower. You won't get a reading of air tightness but you will be able to go around and find any leaks and deal with them. Set it up so the blower extracts air so any leaks will be blowing in and be easy to find. 1 1 Link to comment Share on other sites More sharing options...
Adsibob Posted February 6, 2022 Share Posted February 6, 2022 Sorry, but I'm really confused. How does this help find leaks? How do you feel for leaks. Are you blowing air externally to try and create negative pressure internally and then walking around the house feeling all junctions with your hand to see if any cold air is being sucked in? Link to comment Share on other sites More sharing options...
ProDave Posted February 6, 2022 Share Posted February 6, 2022 Yes the blower in this case is sucking air out of my home made blower door. You then go round looking or feeling for air coming in through any leaks. A Joss stick (other incense sticks are available) is good for making a bit of smoke to see leaks. A telling thing if your air tightness is good, is the building will depressurise enough that if you go and open a door or a window you will get a big whoosh of air entering the building as you open that door or window. 1 Link to comment Share on other sites More sharing options...
saveasteading Posted February 6, 2022 Share Posted February 6, 2022 3 hours ago, Adsibob said: How does this help find leaks The pressure is very high...enough to blow (or suck) open unlatched (even sprung) doors. Therefore any draught will be significant and affect a candle/ smoke match. As ProDave has explained previously, the official testers just want to give you a rating, and aren't keen on improving your airtightness, hence his diy before the test. 1 Link to comment Share on other sites More sharing options...
Adam2 Posted March 5, 2022 Author Share Posted March 5, 2022 Tadaaa worked very well. Just used jump leads and an old but of cable with a couple of spades on the end. Found some small leaks and very helpfully found one of our huge sliding doors was ok at the bottom but not the top along the closing edge so the door may not be fitted straight. So worthwhile. 3 Link to comment Share on other sites More sharing options...
saveasteading Posted March 5, 2022 Share Posted March 5, 2022 5 minutes ago, Adam2 said: Found some small leaks By what means? wetted finger or smoke? Link to comment Share on other sites More sharing options...
Adam2 Posted March 6, 2022 Author Share Posted March 6, 2022 15 hours ago, saveasteading said: By what means? wetted finger or smoke? Combination, back of hand and Jos sticks. Not the smoke matches as I of course left them at home but they only burn for 20 secs a time so not that useful probably. House now smells of sandalwood 1 Link to comment Share on other sites More sharing options...
saveasteading Posted March 6, 2022 Share Posted March 6, 2022 I'm really interested because I have never pre-tested, and the tester has never been prepared to look for improvements, when the test is 'good' but I want superb. So you found some major leaks and haven't sorted them yet, so minor ones still to be found? Do you go round with the smoke around window perimeters, skirtings, covings etc? Did you tape over extract fans/drains? Link to comment Share on other sites More sharing options...
Adam2 Posted March 6, 2022 Author Share Posted March 6, 2022 The car fan is really effective at de-pressurising the house so the fact that we had some known issues eg ply in doorways didn't really matter as for sure there was air coming in from there but with the fan strength you can still detect other air leaks. Did cover WC waste pipes and obvious holes but we didn't spend too much time on that. Construction is ICF so we focussed on the risk areas of window/sliding doors and roof to wall junctions. Holding a burning stick we watched the smoke - if the smoke was disturbed then we looked for the source and taped it. Takes a while to move slowly around all areas but 2 people 4 hours and pretty thoroughly done. Some areas will need a bit more time to fix and will deal with them next week - the window installers put tape in all required placed but in a few areas they taped onto dusty blocks which is useless of course so we'll remove, prime and re-tape. The roof junction seemed OK - maybe some small air leaks so will see how best to deal with that - probably some plastic fixed with a batten along the wall in ceiling void and then a batten pinning this onto a joist. Worst areas we could find were a few window corners that weren't taped very well. We don't have external render on yet or plasterboard inside so things should only improve from here on! 1 Link to comment Share on other sites More sharing options...
saveasteading Posted March 6, 2022 Share Posted March 6, 2022 7 minutes ago, Adam2 said: 2 people 4 hours A lot of joss sticks, and you couldn't open a window. 2 Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now