In the solum, can't see the air bricks?

[MoonMan2]

I have many air bricks around the house, about 2 levels above ground level. I have just had holes cut through my floor boards so I can see into the solum. This is what I see.

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• MoonMan2
• 1 Sep 2010
• 1

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• MoonMan2
• 1 Sep 2010
• 1

There is about 4 air bricks where these phots have been taken, why can't I see any?





This is the downstairs toilet which has had the floor removed.

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• MoonMan2
• 1 Sep 2010
• 1

To my calculations, comparing to outside, there should be an air brick right where this block of wood is (Joist?)

Is there something wrong?

 

[r896neo]

Firstly in reply to your other post where you asked about the weep holes they are there to drain any water from the cavity not to vent it. They are as you saw above windows so water collecting on top of a catnic style lintel can escape. Likewise there as some at the base of your cavity wall where the solid footing starts.

A joist running very close to an airbrick is quite common as obviously a joist has to be tight to the wall.

As regards the smell do you have any open drains? You will get very strong damp musty smells from a drain that is open including traps and wastes which are fitted but haven't had any water in them yet to close them off. This will be especially strong when it's hot.

Looking again at your photo that bag stuffed into the pan adaptor is a prime candidate. Seal that and any other open pipes or traps properly with duck tape and plastic then see if the smell persists

 

[MoonMan2]

Done.

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• MoonMan2
• 1 Sep 2010
• 2

I will see if this makes a difference to odour.

Thanks for your response about the weep holes.( //www.diynot.com/forums/viewtopic.php?p=1722241#1722241) It is the only difference I can see between the main house and the extension, ie the extension has weep holes all round where the solid footing starts but the main house has NONE where the footing starts.

It does seem odd that it is normal for joists to be pressed against the air bricks. In comparing the extension with the main house, I have noticed that the air bricks are just one brick up from the ground, compared to 2.5 or so in the main house. So from this it looks like the air vents are below the joists in the extension, hence allowing better ventilation.

I just get the feeling that my solum and cavity(in main house) is being suffocated

 

[Nige F]

I kind of agree with you . My house has loads of airbricks that have obviously been retro fitted ( there was a problem with condensation on walls etc. when I bought it ) so I lifted a few boards and found that all the air bricks did was ventilate/let freezing cold air through the cavity wall . And up into the roofspace . I soon got a long thin sds drill and drilled right through from outside in a corner of the airbrick - Sure enough , I then located where the air should be going -under the floor - cut out the corresponding bricks , and I`ve got draughts under floor , instead of up the cavity, where the freezing inner wall surface was getting condensation/mould . .

 

[MoonMan2]

Nigel F, what would you advist me to do?

 

[MoonMan2]

This is another picture from below the kitchen, just at the backdoor.

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• MoonMan2
• 2 Sep 2010
• 1

What is the white stuff?

 

[Nige F]

White stuff is efflorescence - : I would advise you to do the drill test - then you will see exactly where the air bricks should be on the inside maybe take one out completely and look inside the cavity .

 

[MoonMan2]

I have realised that a couple of air brick vents are clear in the solum below the dining room.

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• MoonMan2
• 4 Sep 2010
• 1

Hope you can see the green garden canes at the middle of photo up slightly, they have been poked through from the outside of air vents.
The second one is the air brick sleeve which can be seen clearly on the far right and up slightly.

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• MoonMan2
• 4 Sep 2010
• 1

The above photo shows an air brick sleeve vent to the right of middle, with a copper pipe blocking it.

Going back to the 1st picture, it can be seen that the reason why this vent is open is because there is no wood blocking it. Not sure if it is a chance occurance but the dinning room does smell a bit better than the rest of the downstairs - is this because some of the vents are clear?

I went round the rest of the house poking the garden cane through the vents and I was met with wood every time. I believe the rest of the vents are blocked, with the air bricks being exactly at the bottom of the wooden beams all round the house excluding these few in the dinning room. I have thought of a solution and that is to simply get someone to replace the single air brick vents with double ones.

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• MoonMan2
• 4 Sep 2010
• 1

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• MoonMan2
• 4 Sep 2010
• 1

I say this because I am worried that if I simply asked the brickie to move the single vents one brick lower it would interfere with the wooden beam/joist (dont know name) as he chisels through as the line of mortar(inner cavity) appears to be right where the wooden beam is. By getting him to increase the size of the inner cavity opening to fit double air brick, will this reduce the chance of him doing damage to the wooden beams?

Another question, is it easy enough for the brickie to install a double air brick vent, considering it would mean removing two 'half bricks' below the current single air vent? For example in this photo below.

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• MoonMan2
• 4 Sep 2010
• 1

 

[JohnD]

I have known people drill a few large holes in the centre lines of the joist to let the air through

I see that the bit of copper pipe just in front of the vent has no insulation on it, so it can freeze.

 

[Nige F]

Good idea with the garden canes I knew I had to remove bricks so I used the long drill to identify the corner of the airbrick exactly. Also a good idea to have larger brick fitted - easy job for a brickie. Leave the joists but get the pipe lagged

 

[ajrobb]

Sorry of this is off topic, but the insulation doesn't look right to me:

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• MoonMan2
• 1 Sep 2010
• 1

It looks to me like the netting has just been laid across the joists with hardly any insulation thickness by the joists. I think the netting should have been run down the side of the joists and stapled. The photo of the kitchen looks better.

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• MoonMan2
• 2 Sep 2010
• 1

 

[MoonMan2]

Thanks guys, being looking at the pictures more closely.

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• MoonMan2
• 5 Sep 2010
• 1

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• MoonMan2
• 5 Sep 2010
• 1

These were taken at the entrance hallway. There are two air brick vents on the outside. I have to admit I am now doubting that my idea of using double ventilation bricks will work, cause the bricks look like they are laid long ways and also it looks like these bricks would need to be removed to have double air bricks, but they are supporting the wooden beam. I hope this diagram makes it clear what i am trying to say.

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• MoonMan2
• 5 Sep 2010
• 1

Is it back to the drawing board?

 

[MoonMan2]

Right getting a bit stuck with this one, so looking at all options now.

I have known people drill a few large holes in the centre lines of the joist to let the air through.

In considering what you have said JohnD and in relation to my drawing(if my drawing is accurate, would welcome comment), would that mean drilling from inside the solum void at the exact point where it is known that the air brick openings are?

Will this comprimise the joists or beam supporting the joists in anyway?

 

[JohnD]

yes, but there are some rules for drilling joists, which I haven't got. You have to drill the holes in the centre line of the joist, but I don't remember the permitted size and spacing.

In your sketch, if the "wooden beam" is the joist, it appears to be resting on the wall plate, so would be safe to drill or cut

I would dab cut edges with Cuprinol Green to discourage insects or rot.

If you can clear away the builders rubbish from under the floor, especially scrap wood which can harbour insects or rot, it looks to me like you will probably have clean, dry concrete, probably laid on a DPM, so your subfloor will be pretty dry compared to older or faulty houses.

 

[stuart45]

Firstly in reply to your other post where you asked about the weep holes they are there to drain any water from the cavity not to vent it.

Weep holes often have a dual purpose of venting and draining a cavity, especially in timber framed houses. Sometimes they are put in solely to vent as shown in the photos. Here they have been put in timber framed houses beneath the frames and eaves where water won't penetrate.

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• stuart45
• 7 Sep 2010
• 1

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• stuart45
• 7 Sep 2010
• 1

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