Cavity Wall Bridging

[frodo]

Hi y'all
I think I have a problem with an upstairs concrete floor which bridges right over the cavity wall space. It seems to be causing damp to intrude to internal walls when weather is severely wet and windy. Would this be the cause and can I do much about it? Any ideas. Desperate.

 

[DAZB]

I would check the pointing on your external wall as it may be letting in wind driven rain if it is old and loose. A pair of binoculars will come in handy if you like to keep your feet on the ground.

 

[frodo]

Thanks DAZB
The external wall is actually stucco/rough das over concrete blocks and appears in fairly decent condition. That's the preferred building method around here it seems, two courses of concrete blocks with a cavity twixt them, on newer properties this has insulation in the cavity but ours was built in the late 60's and has none. Local people tell me that they put the support ties and concrete across the cavity when they added the 1st floor and they all reckon this is the problem. Dunno, what do you think?

 

[DAZB]

Difficult one this but if water is getting in then the stucco must be perished somewhere. The problem will be actually pinpointing the breach because it may look fine even from close range but if water gets in behind then it may be ''blown'' ( lifted from the wall ) and the water will then find it's way to the slab and to the interior wall. It will probably need a ladder inspection and as well as checking for any obvious signs of ingress give various areas of the wall light taps with your knuckle and if you get a hollow sound it's not good news. Is it viable to remove the stucco from the problem area and have it redone because the chances are that if the house is over 30 years old then it may have served it's time anyway?

 

[frodo]

Thanks DAZB - I'll check it out at first opportunity. There is some evidence to support your theory particularly around an old chimney stack (not used and blocked up at present) and yes I suppose the stucco is over 30 yrs old now so maybe need replacing/patching. When this has been done would Thompsons Water Seal help I suppose? Thanks again.

 

[DAZB]

I am not sure about Thompsons Water Seal as I have never used it but a coat of PVA will bond and seal the brickwork prior to new render. Good luck.