Having an air test next week, any tips?

[jack]

1 minute ago, Dreadnaught said:

Not witnessed one yet but I believe they do both and take an average of a series.

 

Yup.

[BotusBuild]

They can do either - each tester has their preference. depends whether you like to see the "magic smoke" flowing away from a leak or into it ?

[lizzie]

19 hours ago, newhome said:

QQ. Why would you want to do something ‘temporary’ for the test as surely if you remove said lubricant etc afterwards it’s not giving a realistic measure of how airtight the house is in normal use? 

My house was (and still is to some extent) very leaky (air and water) on day of test but as TF supplier contracts to give an air test cert of 6 the testers stuck tape everywhere to get the result so TF co could get their final instalment. They would not have walked away without getting the 'right' result on the day. The testers told me to sort it out afterwards as house was not properly airtight and that result would not be achieved again unless we sorted all the leaking.  I guess a company employed direct by owner would be less likely to do the temp fixes as they have no interest in getting it to a certain level as there is no third party involved.

[joe90]

47 minutes ago, lizzie said:

My house was (and still is to some extent) very leaky (air and water) on day of test but as TF supplier contracts to give an air test cert of 6 the testers stuck tape everywhere to get the result so TF co could get their final instalment. They would not have walked away without getting the 'right' result on the day. The testers told me to sort it out afterwards as house was not properly airtight and that result would not be achieved again unless we sorted all the leaking.  I guess a company employed direct by owner would be less likely to do the temp fixes as they have no interest in getting it to a certain level as there is no third party involved.

 

Thats one reason I don’t like airtight membranes that are buried in the build. Thinking about it apart from door and window seals the only vulnerable bits are the osb lining the warm roof which was glued to death on construction (still visible to fix) and the wall to timber roof joint which is still just about visible. The reason being timber and blockwork expand and contract at different rates but it is foamed to death.

[Ed Davies]

9 hours ago, lizzie said:

My house was (and still is to some extent) very leaky (air and water) on day of test but as TF supplier contracts to give an air test cert of 6 the testers stuck tape everywhere to get the result so TF co could get their final instalment.

 

Surely the TF company contracted to achieve a certain level of airtightness. Why would you allow them to cheat on this?

[Pete]

10 hours ago, joe90 said:

The only holes are ASHP pipes and these are sealed with silicone, the  MVHR external terminals will be temporary sealed up. Question, do they pressurise the house or create a vacuum?, only asking as it will be easier to vaccuum the house and see draughts (if any) with my e cig inside the house! I think if I have any leaks it will be window or door seals which should be fairly easy to fix.

Mine just created a vacuum as they said it was quicker and get a reading sooner. It also told them if the test was going to be a good result by doing the vacuum first. I suppose they may have done a pressure test if my result was poor but I got 0.56 with a big air leak around my unfinished windows so need to do further testing.

[lizzie]

52 minutes ago, Ed Davies said:

 

Surely the TF company contracted to achieve a certain level of airtightness. Why would you allow them to cheat on this?

@Ed Davies can of worms here best left

[Jeremy Harris]

The standard method requires both a pressurisation and depressurisation test, with the result being the average of the two.  There will always be a difference, because outward opening windows and doors will seal better when depressurised, whereas inward opening doors will seal better when pressurised.  A house with all inward opening doors and windows will often give a better result when the house is pressurised and vice versa, hence the need to do both tests and average the resuts.

[Jeremy Harris]

3 minutes ago, lizzie said:

@Ed Davies can of worms here best left

 

Haven't we been here already and confirmed that your result was better than the 0.6 ACH guaranteed, and that you were under the misapprehension that a higher figure was better, and that your sub 0.6 ACH resut was really pretty damned good?

 

It's normal to tape up apertures like the ducts, pipes and around the air test kit where it fits to the window/door.

[Ed Davies]

22 hours ago, lizzie said:

The testers told me to sort it out afterwards as house was not properly airtight and that result would not be achieved again unless we sorted all the leaking.

 

[epsilonGreedy]

On 14/05/2019 at 09:02, joe90 said:

I have just booked our air test for next Monday and wondered if anyone had any tips about finding any air leaks I may have?

 

 

Do you have MVHR? If not be prepared to create some extra holes.

 

I visited another self builder now on his second house. His previous house was trad brick & block without MVHR. He had not paid much attention to air tightness with his diyMax build beyond just wanting a decent tidy standard and was surprised to get an air test result of 2.9 which was too airtight without MVHR. In order to avoid later building control hassles he and his air tester had to introduce some holes to get a final result above 3.0

Edited May 16, 2019 by epsilonGreedy

[Ed Davies]

@joe90 has MVHR.

[joe90]

I just need to work out how to block the external vents under the eaves?

[epsilonGreedy]

16 minutes ago, joe90 said:

I just need to work out how to block the external vents under the eaves?

 

 

Have you considered disconnecting at the heat exchanger and blocking the ducts there?

[lizzie]

13 hours ago, JSHarris said:

 

Haven't we been here already and confirmed that your result was better than the 0.6 ACH guaranteed, and that you were under the misapprehension that a higher figure was better, and that your sub 0.6 ACH resut was really pretty damned good?

 

It's normal to tape up apertures like the ducts, pipes and around the air test kit where it fits to the window/door.

Jeremy I am not disputing my result I am merely commenting on the process that was gone through to achieve it.  The testers were not going to leave without it achieving the contracted result and so they taped up gaps and holes etc.  This is not a complaint it is an observation and comment on the process and you were not here you did not see it so you cannot give an opinion. My gaps were not normal gaps such as the door, apertures, ducts etc I had gaps in all sorts of places plus I had gaps around the windows and water coming in all over the place....it was not airtight on the day and it was made airtight by temporary means with the caveat to sort it properly afterwards.  I arrived right at the end of the test and that was what they told me. We used a lot of expanding foam and tape afterwards to try and seal up the gaps as best we could.

 

It just shows that a good result can be achieved  on the day if testers want to achieve it, it does not mean that the house would achieve the same score if it were tested again. I do wonder what it would score now....my hope is better but given I have dust and grit coming in under my slider thresholds I suspect not.

 

I have no wish to hijack this thread with old news so no further comment from me.

Edited May 16, 2019 by lizzie

[Jeremy Harris]

I do understand that you had problems with your doors/windows leaking badly, but as they were not a part of the TF companies airtightness responsibility, then it seems reasonable that the door/window companies poor workmanship shouldn't be allowed to compromise the sign off of the rest of the structure, especially as you wrote this about the cause of some of those leaks:

 

 

Arguably you could have opted to get another air test done after the door/window remedial work had been completed.  Might have been worthwhile in determining whether the later sealing work had been effective.

[joe90]

Right, after having to go away for the weekend to sort family problems I am not ready fir the air test this afternoon, I went to a Vape shop and was told I would have to spend £40 fir one that delivered the amount of smoke I required!!! (And you cannot take it back afterwards). I was then told Argos did party fog machines (that I could take back afterwards) but they have stopped doing them. Apart from buying some fags (which I am reluctant to do as I have had throat cancer twice and don’t smoke!) I cannot think of another way. Ha, just looked and Screwfix do smoke capsules, anyone used these?, are they good enough? It would be good if I do have some leaks that I can pinpoint them and think smoke is the only way.

[lizzie]

Can you use one of the smoke detector tester cans they make smoke....or maybe its not enough smoke.  Otherwise there is always the faulty hairdryer method as used (accidentally) by me last year.....that makes a lot of smoke!

[Jeremy Harris]

I found joss sticks worked OK when I was tracking down air leaks in our old house.  The smell did result in me being asked a few searching questions about what I'd been doing, though...

[PeterW]

14 minutes ago, joe90 said:

Ha, just looked and Screwfix do smoke capsules, anyone used these?, 

 

Just don’t..!!! They are disgusting and will make stuff smell ..!!

[joe90]

If I knew someone who kept bees I would ask to borrow their smoker!

[joe90]

Just found Holland and Barrett in Bude sell incense sticks , I am off to the seaside?.

[SteamyTea]

I am off to buy a packet of Marlboro, see you later.

[joe90]

Well that went well, Steamy Tea and me running round with joss sticks, found an ASHP pipe that I had forgotten to silicon up but a few windows leaked where the timber had shrunk away from the plaster a little, which will be sorted on re decorating after the house has settled. The tester said it was better than he was used to. Will get the official figures soon so will post them (if they are good enough to hold my head up here on the forum). We also opened the loft hatch to see if the warm roof was as airtight as we thought (hoped) and it looked good.

[ProDave]

I am puzzled why he could not tell you the result immediately?  The only time I was present for one, the result was known immediately.