draught check

[jayroc2k]

 Having just completed a whole house renovation and reused all of the old doors, however all the windows are brand-new, however the house still seems very draughty.

 

I am trying to find a way to find where the drafts are coming from, I have tried using flames which does not work or an incense stick but both are quite tedious and not very effective.

 

Any ideas how to trace tiny/big drafts around the house. 

 

Another annoyance is the flappy exterior drafts vent on the bathroom extractors keeps “slapping” as the wind causes it to constantly flaps noisily. Any ideas for replacing it. The actual unit also has its own flaps which is constantly doing the same, noisily flapping constantly. It is this one and has a flap inside 

 

https://www.screwfix.com/p/manrose-cowl-vent-white-100-x-100mm/16195

 

I suspect drafts are coming from

- extractor vents

- chimney

- kitchen extractors which is ducted upwards via the vertical chimney (I can hear the air blowing in)

- skirting boards.

- two air bricks

- small cracks around the stairs above the vented cellar

 

I am tempted to pay for an air test but surely I can do most of the investigation DIY. It’s a Victorian house renovated completely. 

 

i need a ways to test and find the big leaks. Thanks  

 

P.S. Draft should have been draught! 

Edited January 8, 2019 by jayroc2k

[Ed Davies]

A few people have made their own blower door or window inserts. Not difficult with an electric car radiator fan, a 12V power supply, bit of OSB and some sticky-back plastic. Obviously not calibrated to measure the actual flow rates but very useful for depressurising [¹] the house to then use a smoke source to trace air movements.

 

[¹] or pressurising though that's less helpful for finding leaks.

[Jeremy Harris]

Here's a couple of photos of the unit I made up to find and try and seal air leaks up on our old house:

 

 

 

 

It's pretty much exactly as @Ed Davies described above, a car radiator fan fitted into a bit of MDF that was cut to be a tight fit in an opened window.  I swapped the original motor for a brushless DC one, mainly because I found that I could get better speed control this way, but also because the original brushed motor fitted to the fan was on its last legs, and made a heck of a noise.

 

It was extremely effective at finding leaks, especially when set to depressurise the house.  Many of the leaks could be found just from the loud noise they made; so no real need for anything fancy in the way of leak detection.  Some of the worst leaks in that old house were where the ceiling met the internal plastered block walls (it was a bungalow).  The gaps were tiny, too hard to see clearly, yet howled like banshees when the fan was running.

[TerryE]

We achieved under 0.6 ACH on our first test which was the contracted MBC value,  so our airtightness / insulation crew didn't bother going round the fenestration looking for leaks.  I like @JSHarris tester and might do that, but to be honest I found that a gentle wind outside creating a pressure drop across the house was enough to be able to feel the slight draft you get with the back of a hand on a couple of windows and a door that the Internorm installers didn't properly adjust .  I did adjust these to tighten the seal, so we are now probably well under the test value.

[Onoff]

2 hours ago, JSHarris said:

Here's a couple of photos of the unit I made up to find and try and seal air leaks up on our old house:

 

 

 

 

It's pretty much exactly as @Ed Davies described above, a car radiator fan fitted into a bit of MDF that was cut to be a tight fit in an opened window.  I swapped the original motor for a brushless DC one, mainly because I found that I could get better speed control this way, but also because the original brushed motor fitted to the fan was on its last legs, and made a heck of a noise.

 

It was extremely effective at finding leaks, especially when set to depressurise the house.  Many of the leaks could found just from the loud noise they made; so no real need for anything fancy in the way of leak detection.  Some of the worst leaks in that old house were where the ceiling met the internal plastered block walls (it was a bungalow).  The gaps were tiny, too hard to see clearly, yet howled like banshees when the fan was running.

 

So this is set up to suck air OUT of the house?

 

Then you go around edges, junctions etc listening / feeling/ holding a bit of tissue and seeing if it "wafts"?

[Jeremy Harris]

On 06/01/2019 at 13:04, Onoff said:

 

So this is set up to suck air OUT of the house?

 

Then you go around edges, junctions etc listening / feeling/ holding a bit of tissue and seeing if it "wafts"?

 

 

Yes, although you can use it either way.  I found it easier to find leaks that were blowing into the house, as they create draughts you can feel with your hand, or hear if they are big ones.

[Ed Davies]

2 hours ago, Onoff said:

Then you go around edges, junctions etc listening / feeling/ holding a bit of tissue and seeing if it "wafts"? 

 

Yes. People also use a candle or something to produce some smoke to see what's happening.

[ProDave]

I did the same thing but using an old large office fan and a large sheet or cardboard to cover a whole door opening and lots of tape to seal it. As alredy noted, set the fan to extract and you should easily find all the draughts coming in.

 

But you have answered your own question. You have open fan vents, an open cooker hood vent, an open chimney and probably an air inlet vent for the stove.  And I bet you have a letterbox in  the door and possibly a cat flap?  Our last house had a total of 9 such openings, plus trickle ventilators on all the windows, and the result was it was draughty, not because of any particular failings in the construction, but all the ventilation and other openings.

 

Our new house has none of these. All ventilated by the mvhr system that has just 1 inlet and 1 outlet, the stove is room sealed to the flue and the ducted air intake no letterbox and no cat flap, and is so much better sealed and completely free of any draughts detectable.

 

You might well find some minor leaks in the building that you can  seal up but my suspicion most of the problems will be the ventilation fan openings and there is not much you can do about that.

 

A good "seat of the pants" test, it with a sell sealed house, like our new one, on a windy day you can open 1 door or 1 window and you won't get a draught and the door or window will not blow shut or further open.  Our previous house, if you did that, wind entering or leaving one of the many ventilation holes would blow that door or window open or shut.

 

The flaps on those fans seem to serve just to irritate you and rattle in the wind and have very little practical effect at sealing the openings.

[jayroc2k]

Thanks for the useful ideas.

Any ideas of replacement draught vents for the bathroom extractor fans that actually work.

 

i found this https://www.cheshiredesigncentre.co.uk/anti-draught-air-vent.html

I also need an equivalent for the chimney Cap. 

 

 What I find interesting is that in a friends well sealed apartment, when one window is fully open on one side of the apartment while all the windows are closed, there is no draught,  in fact they need to open windows on both aspects to get wind going through.

 

 I don’t have trickle vents but I suspect the brand-new timber sash windows are not as air tight as I expected

 

[ProDave]

How did you get away fitting windows without trickle vents if you don't have mvhr?

[PeterW]

21 minutes ago, ProDave said:

How did you get away fitting windows without trickle vents if you don't have mvhr?

 

Refurb wouldn’t need them. 

[Ferdinand]

54 minutes ago, jayroc2k said:

Any ideas of replacement draught vents for the bathroom extractor fans that actually work.

 

I think the devil is in the detail here.

 

I used this one in a renovation back in 2016 to avoid th8s issue, and have not had any problems or complaints from the Ts and I ask for any issues with the house every few months. I think it has a single flap rather than louvres, so would be less rattly. But mine was at the far end of longish run from a bathroom extractor fan and high on a gable, and I always fit fans with integral backdraught shutters anyway .. so very much belt and braces.

https://www.amazon.co.uk/dp/B01G3YNLJ8/ref=pe_3187911_189395841_TE_dp_1

 

I am not sure if it is better if different to yours, but the Amazon page suggests alternatives, and you can also get spring loaded backdraught shutters that you can fit inline, and are therefore away from the wind and quieter as no rattle.

 

eg https://www.amazon.co.uk/100mm-Extractor-Draught-Shutter-Spring/dp/B00A50NDEU/

 

I think you are going to need to order stuff and experiment.

 

BTW if you edit te 1st post you should be able to bugger-down the title spelling by editing the title field.

 

F

 

 

Edited January 7, 2019 by Ferdinand

[Ferdinand]

For draughts hunting you can get a thing called a smoke pencil to find small air movements; it does what it says on the tin.

Edited January 7, 2019 by Ferdinand

[jayroc2k]

13 hours ago, PeterW said:

 

Refurb wouldn’t need them. 

You are right. The building control guy said it was like for like and was pleased it was an upgrade. Said the old house would be draughty so trickle vent is an over kill. 

[Vijay]

Would incense sticks work too? - added bonus of a nice smell

 

[Jeremy Harris]

1 hour ago, Vijay said:

Would incense sticks work too? - added bonus of a nice smell

 

 

Yes!  I had a bundle of joss sticks sat in a drawer and used them to track down smaller leaks.  SWMBO was not impressed with the smell of the house when she got home and thought I'd been having a crafty toke while she was out...

[Ferdinand]

51 minutes ago, JSHarris said:

 

Yes!  I had a bundle of joss sticks sat in a drawer and used them to track down smaller leaks.  SWMBO was not impressed with the smell of the house when she got home and thought I'd been having a crafty toke while she was out...

 

SO that is ganja too, then.

 

Has Levi Root self-built yet?

 

His twitter handle is @levismokehouse.