Another airbrick thread

[daveaspy]

I have removed a few air bricks today to investigate what is behind them and have some concerns.

I have a 1930s semi. There is only 1 air brick at the front which is on the bay window (9x6 original louvered clay). Other houses in the street have at least 2 and some 3 but one has probably been lost due to a porch and the other side of the bay is a raised flower bed plus the gas meter (I think the gas pipe might enter somewhere near a possible airbrick behing the bed??).

The earth under the suspended floor is quite damp but no puddles, however some of the joists near the (cold?) walls have condensation droplets on them as well as on the gas pipe.

The bricks I have removed are at the rear and side of the house and I have some pictures. Worth noting none of them are sleeved and so plenty of insulation blocking airflow behind them...

One at the rear - note the joist inside, about 2" gap between joist and inner leaf.
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Another rear one, just over 3m from the first one. Again, a joist may(?) impede airflow?
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Third rear brick but looks pointless to me as there is solid floor behing this wall, and nothing on the inner leaf so whats it for? I plan to replace this with a solid brick.
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A side air brick - not a good path through to the under floor
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Another side air brick and a pic from the inside too
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One of the biggest issues all around is high ground level outside meaning the airbricks are close to floor level - is this in itself a problem? I cannot decide if a joist close to an airbrick will give it better ventilation or make it colder and more prone to condensation?? I have had a good feel around and all the cavity insulation is dry inside.

At the back of the house I effectively have 2 bricks over 3m apart. In between them is a double patio door. I feel like I should add an extra air brick between them but is it ok to do that under patio doors?

 

[noseall]

So long as the air bricks are clear then air will be pulled in and pushed out.

Ask anyone who have any high level air bricks in walls.

Seriously as long as they are not impeded the air will move.

Adding more will do no harm even under a patio door though not ideal.

 

[gregers]

from the lack of cobwebs hanging from your joists,i would say the air movement under that floor is sound.from the pics they all look in very good condition,as said adding more will not harm the exercise.

 

[daveaspy]

from the lack of cobwebs hanging from your joists,i would say the air movement under that floor is sound.from the pics they all look in very good condition,as said adding more will not harm the exercise.

All the joists I can see look quite new to me - you can still see the green tinge which I assume means it is treated timber. My guess would be these were replaced maybe 5 years ago?

There is a definite musty smell coming from down there so I don't believe the ventilation was working too well, I'll see how it goes now I have cleaned out all the air bricks but I do think I need to get an extra one in the front somehow.

I haven't fixed the bricks back in yet - just sat them in the hole to stop any little visitors. I have some plastic sleeves I want to put in, and some plastic air bricks but not sure whether to use them or put the old clay ones back?