Installing Vent Holes in Old Brick Walls

mskhanca · 10-26-2012, 10:13 PM

I bought a house two years earlier. After about 10 months, I noticed some mold growing on some portions of exterior walls. I have removed the drywall/plaster from one of the wall and noticed that the wall is actually build with a layer of bricks outside and a layer of blocks inside with no building wrap. There was a rough plaster on inner side of blocks on which a felt and furring strips were laid to put the drywall on. I noticed various wet spots on plaster. I have sealed all cracks from outside and insulated the wall from inside. Now I am afraid, that if some water again trapped inside the wall, it may not dry and there may be another mold problem.

What I want to do: I want to drill 3/4 inch holes at an angle from outside in the mortor joints, through to the face of blocks (i.e. drill holes in outer layer of bricks) install perforated pipes with some grating material so that bugs may not enter but the water may drain and air may circulate. I want to install these holes every 4 feet. I just want comments that whether this idea work

stuart45 · 10-27-2012, 07:55 AM

mskhanca,
Is there a cavity between the brick and block of 2-3 inches, or is it a solid wall? Do you live in a damp climate?
Is the damp at the top or bottom of the walls?
Can you put on a few photos of the inside and outside walls?

mskhanca · 10-31-2012, 12:09 PM

Quote:

Originally Posted by stuart45

mskhanca,
Is there a cavity between the brick and block of 2-3 inches, or is it a solid wall? Do you live in a damp climate?
Is the damp at the top or bottom of the walls?
Can you put on a few photos of the inside and outside walls?

There is no cavity as such. The houses at that time were build with block walls instead of lumber framing (i.e instead of lumber framing, blocks walls were erected and roofing etc was then installed) After completion of roof, Brick wall was constructed outside the block wall. I don't have photos but it is simply a layer of blocks and layer of bricks. There may be a cavity in mils not in inches

Thanks

stuart45 · 10-31-2012, 06:36 PM

There are quite a few houses here with that kind of construction, although the brickwork and blockwork were usually put up together.
I am guessing you live in Canada calling it lumber and using the metric system.
The idea with a solid 9 inch wall is that the moisture will only penetrate about 4 or 5 inches before the heat from inside makes it evaporate back out.
However gaps between the brick and block can allow water to penetrate, especially if the brick pointing is poor and you get a lot of driving rain. This type of wall isn't used on housing now.
Condensation also is a big cause of mould.

mskhanca · 10-31-2012, 08:54 PM

Quote:

Originally Posted by stuart45

There are quite a few houses here with that kind of construction, although the brickwork and blockwork were usually put up together.
I am guessing you live in Canada calling it lumber and using the metric system.
The idea with a solid 9 inch wall is that the moisture will only penetrate about 4 or 5 inches before the heat from inside makes it evaporate back out.
However gaps between the brick and block can allow water to penetrate, especially if the brick pointing is poor and you get a lot of driving rain. This type of wall isn't used on housing now.
Condensation also is a big cause of mould.

Yes, I live in Canada. I know that these type of houses are not constructed now. The mold problem is due to condensation and may be due to water penetrated through cracks