air bricks

[confidentincompetent]

Hi. My bungalow circia 1960 has solid floors, there are airbricks above damproof course and in each bedroom they are about 6" above skirting. Over the years others have put shut & close covers over the internal side.
Cant see why they were needed as there are no fuel burning/chimmneys in bedrooms. The thing that mystifies me and several other builders is that these vents are not closing the cavity ie if you were to fill cavity's with foam (perish the thought) it would spill out of vents. I always thought airbricks were supposed to close cavity to keep air still. As it is now when wind blows fresh air is circulating through all the cavities. Would you block em off?
John .

 

[greengrass]

If the room is dry and free from condensation, especially around and on the windows then to prove a point block the vent with a board boxing inside and out make sure both sides are sealed properly then watch for condensation over the coming months.
If it appears heavily on the windows and didn't before then it's there to prevent condesation.
If a room is damp with condensation through lack of circulatory air then if you have a fitted wardrobe without a back ie: the back is the wall that will draw moisture and send clothes mouldy. I know it's happened to me a wind whistling through a vent at ceiling level I blocked it up with polystyrene so tight it would have stopped a tank but payed for it by my bedroom window sodden with condensation and mould on my best jacket in the wardrobe. If you get no effect then seal it off permanently.

 

[confidentincompetent]

Thanks for that greengrass m8. Actually they are not air bricks as we know them but a seperate grill each side with the cavity exposed in between, I.E if I take off a grill I can reach inside the cavity. My understanding of cavaties (erm no expert lol) is they should have still air, what I have at the moment is air circulating round the cavaties, puts my hand over one and quite a draught can be felt. I'm going to block em up weekend, might make house warmer in this cold snap .
cheers

 

[jbonding]

if theres that much air blowing through your cavity (no pun intended) it might be worth considering cavity insulation because even though you block it you will be loosing a lot of heat through the walls.

 

[greengrass]

Jbonding is right I've just been discussing it with the neighbour, he had his done in the summer and he now swears the house is warmer, and he's got a bl....y big house, I mean big and bank balance to boot.

Don't seal them permanent you'll be sorry if the room/s start dripping with condensation especially around the windows. Suggest you start by taping sheet of paper over the vent. Paper won't completely seal it and allow a certain amount of ' breathing air' so as not to introduce condensation or damp patches on the walls.

 

[confidentincompetent]

Thanks for your replies. I cut some plywood and temporarily fixed with plumbers mait a few weeks ago. I only moved in 2yrs ago but neighbours have all had their cavitys filled yrs ago so can't answer my query on these bricks. But they do say they had a lot of condensation probs since being filled seems thay had foam, and must say quite a lot of house's I work on seem to have probs with this foam filling. Have asked a couple of builders too but they cant see why the cavties are vented. Oh well will check out the cavity fill later, do they still do the rockwool?

 

[countygardens]

Damn! My house is the same. Might have to have a go with blocking the bleeders as our heating bill is rather large and I wouldnt be suprised to find that is why