Jump to content

Air leakage/tightness test tips


m4tth3wb

Recommended Posts

31 minutes ago, m4tth3wb said:

Hi,

 

We are due our air leakage test soon and are just after some tips for a pass, where does it normally go wrong?

 

The house is plastered now, has kitchen fitted and all final fixes completed.

 

Thanks 

Fingers crossed time

Very little you can don once it is plastered

If it has been dot and dabbed

It should have solid dabs along ceiling and skirting Also around the window reveals and all electrical boxes

Should sail through if it has all been done

 

 

Link to comment
Share on other sites

Closing the door after the horse has bolted! Sealing skirtings to floors -- yikes, ther shouldn't be draughts under the first floor or behind the walls.

 

close up cooker hood duct and fan ducts temporarily, check all trickle vents close properly, check under thresholds and window boards, ceiling roses to first floor should have caulk round where the wires enter, pipes in airing cupboard, first floor joists etc for some info see  this and scan site for more info 

Link to comment
Share on other sites

  • 2 weeks later...

Just had my house tested today and achieved 2.2m3/hm2. In my head I was hoping for less than 2.

I ve done a quick calculation and I think this translates to 1.4 ACH.

 

I had a quick check around for anything obvious - nothing glaringly obvious. We have a lot of glazing so this will probably play its part a little as I could feel very miniscule amounts come through inbetween the frames. Whilst these did nt feel much, I guess they mount up over the sheer volume of glazing we have.

 

I know some of you on here have achieved much better but did nt think this was too bad?

Link to comment
Share on other sites

Well done, vastly superior to most UK housing stock.  True, could have been a little lower, but I think it's a good, solid result.  That's the figure my neighbour obtained for his 200+ m2 house, and his (actual) heating bill is less than 3000 kWh per annum.  

Link to comment
Share on other sites

1 hour ago, Stones said:

Well done, vastly superior to most UK housing stock.  True, could have been a little lower, but I think it's a good, solid result.  That's the figure my neighbour obtained for his 200+ m2 house, and his (actual) heating bill is less than 3000 kWh per annum.  

 

Would be more than happy with 3000kwh! Any idea what his u values are? As said, on my house I do have a lot of glazing so this is likely to hit my overall insulation (from memory, walls are 0.15, roof 0.13, floor 0.13).

Link to comment
Share on other sites

We were only very slightly below the passivhaus 0.6ACH standard on our first test.  Then one of the MBC lads realised he hadn't actually pushed the front door closed!  Second test went much better, but I was surprised we got such a good result with a slightly cracked door.

 

30 minutes ago, Sensus said:

That's with dry-lined masonry, though. Timber frame and wet-plastered masonry are inherently much more airtight, if you do them properly.

 

This document mught be helpful to others:

A_Practical_Guide_to_Building_Air_Tight_Dwellings_NF16.pdf

 

The Denby Dale Passivhaus was built with masonry and a parge layer.  Worth a read of the blog to anyone contemplating it.

Link to comment
Share on other sites

42 minutes ago, Sensus said:

 

As a further digression... I'm very cynical about air test results in general, particularly on masonry dwellings. For reasons I won't bore you with, I've had cause to go back and air test properties 2 or 3 years after they were built, and the differences have been dramatic - mainly due to the inevitable shrinkage cracking you get during the initial drying out period and subsequent moisture/temperature cycles.

 

 

 

I've always held this view. I've seen a lot of new builds post completion and a good deal of them suffer severe shrinking. Primarily down to the shear speed they put them up nothing gets time to dry properly.

  • Like 2
Link to comment
Share on other sites

My experience is that all timber arrives on site about the same, it shrinks a lot during the first heating season and by the end of the second one even the biggest timbers have fully shrunk.

 

site operations including rain, plastering, even plumbing and plasterers spelling water have negligible effects.

 

timber shrinks plates, joists, skirtings, linings, window boards, the key is to design and build so that these do not impact on air tightness.

 

 

Link to comment
Share on other sites

If you are sealing a timber framed building properly, I cannot envisage a situation where later shrinkage is going to open up leaks, at least not unless said shrinkage is enough to rip your air tightness tape down the middle?

 

Yes details like a tony tray (we used that, even before I knew the name Tony tray) are essential things to build in at construction stage. How many mass builders even know about things like that, let alone implement it.

 

And do any mass builders seal the building then put a service void so all services run inside the sealed envelope without (or with very few) penetrations?
 

Link to comment
Share on other sites

19 minutes ago, ProDave said:

 

And do any mass builders seal the building then put a service void so all services run inside the sealed envelope without (or with very few) penetrations?
 

 

Not a chance! And as the average home buyer won't even have a clue what air tightness is or means then they never will! 

The regs don't need it and the customer doesn't know they want it! It just ain't going to happen and whilst demand for housing outstrips supply you are simply not going to see any change in regulations to make it happen.

Link to comment
Share on other sites

I let my masonry build sit for close on a year and let it dry out fully. Have had a few tiny cracks but nothing major. I know most builders are on a rush to get the house handed over so they can collect the money and leaving it this long isn't an option. 

I used tapes on all the window and door frames and membranes taped to the walls to seal the floor. All holes for lights etc in the ceilings are all sealed up so am pretty happy with how mine has turned out. As you say it takes time and dedication that most here are willing to do. Didn't need an air test to pass the regs, brought in now in NI though.  

As far as sealing a block wall up a scratch coat and skim finish would be a better option than parge coat,plasterboard and skim in my opinion. Don't get why you build block then stick plasterboard to it.

  • Like 2
Link to comment
Share on other sites

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 account

Sign in

Already have an account? Sign in here.

Sign In Now
×
×
  • Create New...