Penetrating damp on exterior wall below a brick parapet.

Postby pib » Tue Apr 14, 2009 6:15 pm

Symptom - dark staining on the bricks on the first three layers from the parapet - apparent on front side (prevailing wind side only). The parapet is above a single storey extension, extended in 1995. No evidence was evident in 2003. Parapet is a cavity brick with a top layer of bricks laid across the cavity. There is lead flashing on the inside cavity joining the flat roof.

In 2003 the same ground floor extension was further enlarged and the parapet was extended for a further nine feet. In 2008 I first noticed the black discolouration on the first three layers of bricks exactly to the left of the new parapet extension - ie in the earlier extension's parapet wall - about 9 feet in width also.

Advice please...
I am considering - repointing and remortaring the top bricks - most look fairly sound - though there is a small flaked off piece near where the new parapet connects with the older one on the top of the wall.

Should I also add coping stones on the parapet wall? Would these solve all problems?

Could there be a problem with the lead flashings that join the flat roof to the rear of the parapet - ie joining the newer extension flashing to the older one? Is this likely and is there a remedy?

Thanks for reading this. All advice appreciated. :?:
Posts: 2
Joined: Tue Apr 14, 2009 5:45 pm


Simply Build It

Postby brickpat » Tue Apr 21, 2009 8:07 pm

[b]i'm a bit confused what is the over all size of your cavity,how did the close the cavity with a single brick on edge course.repointing i don't think will help'your best bet is to remove a few bricks,i bet there,s no creasing tiles or not even a dpc bridging the cavity,if i'm wright knock that brick on edge off buy your self enough coping stones for the job and a rool of 13"dpc.bed the dpc across the cavity and then bed the coping stones on top of the dpc,make sure coping stones are wide enough to bridge across the cavity.GOOD LUCK [/b]
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Joined: Thu Apr 16, 2009 8:17 pm

Postby pib » Thu May 14, 2009 7:01 pm

Thanks for this reply - sounds a good solution with the damproof layer as well as the coping.
Posts: 2
Joined: Tue Apr 14, 2009 5:45 pm

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