Exterior Brickwork Sealant?

Gastines3

Living in 1950's Bungalow,need to seal brickwork corners to repel any rain ingress.Pointing is O.K. but in winter sometimes get damp patches on inside plaster under bay windows.Have asked in a couple of Builders Merchants for product but they don't seem to know what I'm talking about. Quite probable I'm wrong but believe there used to be a clear paintable product available? Any help with this appreciated.

BJV

Just google exterior brick sealant.

There are loads.

BUT I would get the brick work checked for damp. It could be that the bricks have become porous with age but it could be something else.

You might as well get it checked before you seal it as it could be worse sealing a problem in. 

Grenage

Are you sure it's not condensate or water running in around the windows.

You really don't want that junk on your walls.

thearchitect

I would recommend against sealing brickwork as any penetrating dampness from elsewhere just becomes trapped in the cavity.

Gastines3

Thanks for response. It would seem safer to give it a miss and invetigate further.

Grenage

Gastines3 said:

Thanks for response. It would seem safer to give it a miss and invetigate further.

Bay windows are notorious for being uninsulated, and a real hotspot for condensation to form.  Something that isn't too expensive to rectify with some insulation boards.

FreeBear

Gastines3 said: Living in 1950's Bungalow,need to seal brickwork corners to repel any rain ingress.Pointing is O.K. but in winter sometimes get damp patches on inside plaster under bay windows.

Have a close look at the mastic sealant around the window frames and under the sill. Are windows timber ?

If so, check the condition and make sure they are no rotting.

mi-key

That stuff is basically snake oil. I remember a few years back companies were advertising that they would come out and spray your whole house.

The reason bricks are used for houses is that they will soak in a certain amount of water, but it then evaporates off. To soak all the way through a brick it would need to be saturated. They can also soak up water from the ground and this will also dry off. 

Damp is normally caused by water getting into places the bricks aren't, like joints, very rarely by water soaking all the way through. 

subjecttocontract

We have used Thompson's Water Seal on various materials over the years. We painted it on a small area of brickwork around an exterior tap and hose connector.

stuart45

mi-key said:

Damp is normally caused by water getting into places the bricks aren't, like joints, very rarely by water soaking all the way through. 

It is the joints, especially the cross joints. Tests done by BRE have shown that half filled, tip jointed brickwork can let water into the cavity after 20 mins in heavy, driving rain.

grumbler

Gastines3 said:

Living in 1950's Bungalow,need to seal brickwork corners to repel any rain ingress.Pointing is O.K. but in winter sometimes get damp patches on inside plaster under bay windows.

If it's 'ingress', why is it only under the windows? It's either internal condensation (poorly insulated wall) or a leak (bad external windowsills - water has to drip from them, not  flow to the wall)