Air bricks even though walls are insulated?

Candy53

Hi,

We live in a very draughty old house, and although I thought we had cavity wall insolation, it's a cold house.

I emailed my landlords and asked if we did have the insolation, and they said all necessary insolation had been done to the house, so not to worry.

I was stood outside the front of the house the other day, looking at the 2 air bricks going into a small room, underneath the floorboards, which make the room very draughty, and noticed an air brick above them that goes into the wall cavity space. There is another one at the side of the house.

It surprised me, as I wondered, if there was cavity insulation in there, why they would leave the old air bricks there, as I read somewhere that if damp gets in, it can ruin the insulation.

I got a thin stick, and put it through the air vents, and about 2 inches in, it banged against something solid. Would this be the insulation? If so, is it normal then to have air bricks?


Thanks,
Candy.

Davesnave

Candy53 wrote: »

It surprised me, as I wondered, if there was cavity insulation in there, why they would leave the old air bricks there, as I read somewhere that if damp gets in, it can ruin the insulation.
.

Why would they bother to take the vents out, if they were there first?

Normal levels of dampness will not 'ruin' insulation. The outer leaf of a wall may become damp in bad weather, so the insulation should not be a material that will transfer moisture easily to the inner leaf. Sometimes this happens, which is why cavity insulation may not be the best idea in exposed places.

You say yours is an 'old' house, We all have different ideas about old, but if it's Edwardian or older, it won't have a cavity.

And lastly, landlords/their agents may say anything to avoid work/expense/hassle. You say the house is draughty, so what they told you isn't true.

Candy53

The house was built in 1932. It does have a cavity. Thanks for your reply. Well, I just thought that if they left the air bricks in, the insulation would have oozed out?

Can you, or anyone, tell me if the stick I put through the brick, could have come up against the insulation? Even though there is a gap of about 2 inches between that and the outer brick? We get draughts from all over the house, including under floorboards.


Candy

Kiran

Isulating the cavity will have no effect on draughts under the floor boards. The cavity vents are normally sealed up when cavity wall insulation is installed, as you quite rightly say the insulation would escape otherwise. It depends on the insulation that has been used but you should also be able to see the drill pattern in the walls depending on how the house is finished. They should be about 25mm diameter and regularly spaced.

When you rented the house you should have received an EPC which will state what measures have been undertaken. These can not be relied on as 100% accurate and also be mindful of anything with "assumed" next to it but it can be used as a guide.

HTH

Candy53

Well, there is a drill pattern, but those holes were done when the new damp proofing was put in. Do you know approx how much space there is between the inner and outer bricks? Because, if it's only about 2 inches, the stick could have been hitting the inner bricks. Could old insulation shrink?


Candy.

Kiran

As I said, check the epc as a desktop exercise first, if you havent got your epc then https://www.epcregister.com/reportSearchAddressByPostcode.html put your postcode in here and retrieve the one for your address.

Cavity wall insulation holes will be all over the wall not just at DPC level. Cavity widths are set and can vary considerably. That being said a 50mm cavity would not be uncommon. The insulation should not shrink but depending on the type of insulation it is very compressible. Blown mineral fibre is extremely lightweight.

May be a stupid question, but the vents don't go all the way through to the inside skin of the house do they? Are they visible from inside?

martinsurrey

Davesnave wrote: »

You say yours is an 'old' house, We all have different ideas about old, but if it's Edwardian or older, it won't have a cavity.

Just as an aside, this is not always true, my house is 1888 (so late Victorian) and it has cavity walls on the ground floor.

Not common but not unheard of.

Candy53

Kiran wrote: »

As I said, check the epc as a desktop exercise first, if you havent got your epc then https://www.epcregister.com/reportSearchAddressByPostcode.html put your postcode in here and retrieve the one for your addre

May be a stupid question, but the vents don't go all the way through to the inside skin of the house do they? Are they visible from inside?

No, the 2 vents only go into the wall cavity. Yes, I will check the epc.


Candy

EmmyLou30

The air bricks under the floor are what might be causing the draught in the house, but they are essential to remain open if you don't want the joists to rot! Way to fix the draught? Put some carpet down, or some sort of flooring to cover the gaps in the floorboards. Sounds like there's no cavity wall insulation in your property to me, it's like bean bag balls so would fall out that air brick if it hadn't been sealed off. The fact you can poke a stick in there proves it's not been sealed off.

Furts

Candy53 wrote: »

No, the 2 vents only go into the wall cavity.
Candy

It is not unusual to have a ventilated cavity. It also makes good sense when the home is built of semi engineering bricks, or similar. Basically, the moisture within the cavity needs a draft in order to dry out.

If the air bricks were venting the floor void I would have thought they would have been sleeved with a liner. If done to a reasonable standard then no cavity insulation would get into them - the sleeves would prevent this. But what OP may be detecting is the air brick built into the inner leaf of the wall. If prodded with a "thin stick" this would appear solid.

Hence, I cannot say what the air brick is ventilating.

Candy53

Thanks to you all for your input. I don't feel right about those air bricks, so I read the EPC, and it said 'cavity walls filled' but also said 'assumptions' have to be made on certain things.

I clicked on a link on there that gave you help, and emailed them. I already have a reply, and was told there's no way of checking to see if cavity insulation has been done, so the accessor, who visited our house just before we moved in, in 2010, would have to 'assume' it has been done, unless, he is shown receipts from the company who did it.

They said that I could email the accessor, whose address is on the epc, but I don't know if it's the right thing to do, and, whether they will tell our landlords or not.

Unless the insulation can shrink back over the years, I have my doubts if it's been done. I'm tempted to get my OH to take off one of the air bricks to take a good look inside.


Candy