House is Too Airtight

[Big Jimbo]

I'm up for a fight today. You dont need to fix it. You had your house tested, it scored 4 and you failed. However no account was made for the fact that your existing extractors will add to your uncontrolled ventillation when uncovered after the test. Argue your case with the BCO, and the airtest twat. I have never lost an argument with a BCO yet. Your uncontrolled leakage from your extractors will prob give you an airtest score of over 5. May even be over 6 which would be a fail against the new regs. I don't mind people telling me i'm wrong, but i'm not. (most of the time.) You just need to explain this to both parties. Don't waste money on stuff you don't have to. 

[JohnMo]

Obvious question is why would you even want noisy on demand extract, when you can have silent dMEV.  Greenwood Airvac CV2GIP can be had for £40 to 60 from eBay. Bathrooms and utility only need them as long as you have an extract cooker hood. Need to ensure you have circa 8 to 10mm undercut on the doors, but that should be there anyway, other wise your on demand extract is rubbish.

 

But must say world is going mad, when someone wants to make there house leak more.

[Newlands Ian]

5 minutes ago, JohnMo said:

Obvious question is why would you even want noisy on demand extract, when you can have silent dMEV.  Greenwood Airvac CV2GIP can be had for £40 to 60 from eBay. Bathrooms and utility only need them as long as you have an extract cooker hood. Need to ensure you have circa 8 to 10mm undercut on the doors, but that should be there anyway, other wise your on demand extract is rubbish.

 

But must say world is going mad, when someone wants to make there house leak more.

 Maybe I didn't explain myself properly the first time. I really don't want my house to leak more, what I actually want is for BC to sign-off the warrant!  This is the only item left on their list and I thought it would be quicker and cheaper to get another air-test done after some minor modifications to the house.

Cutting 10mm off every internal door is also a real pain. For the bathrooms maybe but all bedrooms? No way, I like the bedroom doors to be snug. With 10mm undercut the noise leakage is also an issue.

[Newlands Ian]

33 minutes ago, Big Jimbo said:

I'm up for a fight today. You dont need to fix it. You had your house tested, it scored 4 and you failed. However no account was made for the fact that your existing extractors will add to your uncontrolled ventillation when uncovered after the test. Argue your case with the BCO, and the airtest twat. I have never lost an argument with a BCO yet. Your uncontrolled leakage from your extractors will prob give you an airtest score of over 5. May even be over 6 which would be a fail against the new regs. I don't mind people telling me i'm wrong, but i'm not. (most of the time.) You just need to explain this to both parties. Don't waste money on stuff you don't have to. 

Well, an email to BC is free so I'll try to argue my case as a first step. Not holding out much hope but watch this space...

[saveasteading]

45 minutes ago, Newlands Ian said:

BC to sign-off the warrant

I get that. We had the same because it needed some more air to avoid fitting mvhr ( nice but technically difficult).

No air test required but it will be very airtight.

So we've added a vent to tick the box, and it can disappear later.

I suggest just ask bco if that will suffice.

 

Of course, if it turns out too stuffy we might open windows...or admit here that the vent was needed.

 

I might have argued the point with bco but the onsite team tend to do as bco says, and technically he is right.

[Big Jimbo]

Technically he is not right, if your un-taped up extractors will contribute to your uncontrolled air loss., is he?

[nod]

2 hours ago, Newlands Ian said:

My issue is that building control have said either I show them an air test of 5.0 or worse, or I need to change all the fans to dmev and submit an amendment to building warrant. I'm thinking the best and most cost effective short term solution is to alter the building fabric in some way to get the result I need.

I’d h get a second opinion As that is totally wrong 

[JohnMo]

3 minutes ago, nod said:

I’d h get a second opinion As that is totally wrong 

What is totally wrong, that BC will let them amend the result from 4 to 5 and not just insist they install dMEV. Having the option to make a result look worse than it is, just isn't right.

[Kelvin]

Is there also a potential problem of condensation build up if you warm moist getting into the building. I noticed it forming on the back of the alu cladding on the rooflights as I increasingly sealed the house up as I did the rooflights last. I’ve been more concerned with condensation than anything else because it’s so damaging to the building and your health. 

[Kelvin]

1 minute ago, JohnMo said:

What is totally wrong, that BC will let them amend the result from 4 to 5 and not just insist they install dMEV. Having the option to make a result look worse than it is, just isn't right.

I agree. But I know of an example that HH built where they scored just over 1 but couldn’t afford MVHR despite the ducting being in so they slit the window tape and tested until if was above 3.  BC were aware they were doing. Arguably all they care about is that it meets building regs. 

[JohnMo]

4 minutes ago, Kelvin said:

I agree. But I know of an example that HH built where they scored just over 1 but couldn’t afford MVHR despite the ducting being in so they slit the window tape and tested until if was above 3.  BC were aware they were doing. Arguably all they care about is that it meets building regs. 

It gets a tick in the correct box. Then the poor owner, who obviously knows no better really, gets a damp, musty house and wonder why. Possibly saying airtight houses are sh*t, wish we never bothered.

[Newlands Ian]

Well, you wont believe it! When presented with some additional information about the real-world ventilation (number of window trickle vents etc) building control have decided to let me away with it 🙂 RESULT!  

[Big Jimbo]

So the OP got a score of 4, but it's not a proper score because some of his uncontrolled air losses were not taken into account. (They were taped up) So is everybody saying that this was a good, and valid test ? Twat looking for more money for a re-test was wrong. Air tester needs to put this right, not the OP

[Big Jimbo]

Thank you everybody....... BCO are not monsters, or always right. They have done the right thing. Bloke who did the test is still a total knob. I would be all over his firms social media, and leaving a nice (not) review on google etc. What a total waste of time he has caused by being a total twat.

[Big Jimbo]

5 minutes ago, Newlands Ian said:

Well, you wont believe it! When presented with some additional information about the real-world ventilation (number of window trickle vents etc) building control have decided to let me away with it 🙂 RESULT!  

Well done. Just remember the real world is very different to the text books etc. Decent BCO by the sounds of things. Well done for flagging up the expensive piece of shite work you had done, by the twat with qualifications.

[Newlands Ian]

3 minutes ago, Big Jimbo said:

Well done. Just remember the real world is very different to the text books etc. Decent BCO by the sounds of things. Well done for flagging up the expensive piece of shite work you had done, by the twat with qualifications.

Thanks for the nudge in the right direction, Jimbo.  Otherwise I'd be on the phone paying up for another 'friendly' tester and/or drilling holes in my walls 😉

[JohnMo]

@Big Jimbo, when you have finished saying everyone is wrong, have you ever read the spec for an air test. Me thinks not. You are wrong, the tested is supposed to block the things he did.

 

This is the spec the air tester has to work too (attached)

It clearly states

 

P6.4 ensuring that permanently open uncontrolled natural ventilation openings are temporarily sealed

P6.5 ensuring that mechanical ventilation and air conditioning systems are turned off and temporarily sealed to prevent air leakage during testing

P6.8 ensuring that open-flued appliances and controls are temporarily sealed including any internal air inlets

P6.9 ensuring that kitchen and bathroom extractors are temporarily sealed

P6.10 ensuring that all passive stack ventilation points are temporarily sealed

 

ASTATT2-Prepare-building-for-air-tightness-testing.pdf

[Big Jimbo]

Then the test is flawed, and will never give a true result. A bit of common sense should be used when losses that should be taken into account are not. This is obviously what the BCO thought. Are you saying that his uncontrolled losses should not be taken into account ? If that is so then it makes the test a farce, and worthless.

[Big Jimbo]

Not having a dig @JohnMo but if we are going to apply science to a property (or anything) then it should be done right. Air tests are a bit like Saps. A guideline but not a diffinitive. Loads of assumptions are made when doing saps calcs. If you got a C, and were properly tested, and monitored during construction you would be lucky to get an E. 

All these science tests are useful, but dont actually paint a true picture.

So i'm just saying that common sense needs to be considered, which is what the BCO appears to have done.

[JohnMo]

Not disagreeing about common sense. But leaving holes open in the building open isn't testing the rest of the fabric. You know if there is a 100mm hole and a fan is in it. You don't know there's a 100mm hole, cut by accident hiding out the way.  The point is you test every building the same way, not make up the test to suit the outcome you want to see.

 

I have two MVHR units and multiple inlets and outlets, they all get blocked during an air test, because that is ventilation over and above those leaks that occur during a build. You are not testing for known leak sources, you are testing for hidden leaks, to show the overall airtightness of the building.

 

If everyone tests a different way, it's "shite in, shite out" and totally meaningless 

Edited September 5, 2023 by JohnMo

[saveasteading]

50 minutes ago, Big Jimbo said:

Bloke who did the test is still a tota

Man with a fan is taught how to fit it and use it. Not his job to understand the bldg regs.

[Big Jimbo]

It's why I got out of banking. Can't use any common sense, but have to just trust what the computer says. Glad the fella got it sorted with bco rather than having to butcher his doors, and spend money on fans. Good to know that common sense won this time. Yippie for common sense.

[ProDave]

1 hour ago, Big Jimbo said:

Thank you everybody....... BCO are not monsters, or always right. They have done the right thing. Bloke who did the test is still a total knob. I would be all over his firms social media, and leaving a nice (not) review on google etc. What a total waste of time he has caused by being a total twat.

Well not really.  Most people want the best figure they can get.  Unless the OP told him before he started "I don't want any lower than 5.0" how would he know to do other than what he has been instructed to do?

[Big Jimbo]

Your right @ProDave. Thinking of myself. Always on site, and would always make sure I was onsite for an air test.

[saveasteading]

29 minutes ago, Big Jimbo said:

It's why I got out of banking. Can't use any common sense, but have to just trust what the computer says. Glad the fella got it sorted with bco rather than having to butcher his doors, and spend money on fans. Good to know that common sense won this time. Yippie for common sense.

The regs are more guidelines than rules, as stated at their introductions. The bco has to be happy with the solution, so we can sometimes persuade them, if we can show the logic. If that logic coincides with the principles of the actual regulations  then so much the better. If that can be on paper then it can go in the file to close the subject.

I was once told ( non sarcastically) that if I knew so much about it, then present it formally, with calculations and references, so that he was persuaded, and so would be his boss if he happened to look.