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We own a 1930 house we cavity brick walls and have a few damp problems..,

Our render goes over the top of our DPC (damp proof course). The DPC is only about 1cm above the level of the paving. So I need to lower the paving (or put in a dry zone ditch between the paving and the wall) and remove the render.

However the render is very hard, so the brick gets damaged when I try to remove a test section.

Hence it is likely the brick work will need to be re-rendered over the DPC – how can this be done without bridging the DPC?

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how far past (down over) the DPC does the render go? Personally if it was me, I would lower the paving so the top of paving is 150mm (min) below the DPC & the paving falls away from the house (structure). –  Mike Perry Jul 3 '11 at 20:59
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Bridging the DPC is just asking for problems (IMHO).

One possible solution might be:

  • Apply "External Bellcast Bead" just above the DPC (this will form a drip edge).
  • Apply "External Render Stop Bead" just below the DPC (this will allow you to render a plinth from just below external ground level, up to just below the DPC).

Such a method doesn't bridge the DPC.

Regardless of the rendering solution implemented you really need to address the high external ground level in relationship to the PDC. Personally if it was me, I would lower the paving so the top of paving is 150mm (min) below the DPC & the paving falls away from the house (structure).

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You could fix an edge above the DPC and render to that.

If your rendering skills are good you could use a temporary batten and remove it afterwards, or fix a permanent edge.

I've seen these used, but I've no idea what they are called so can't provide a link.

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Thanks, the problem is that the brick below (and above) the DPC is damaged –  Walker Jan 4 '11 at 15:44
    
@ChrisF I believe you are referring to "External Render Stop Bead" or "External Bellcast Bead", please correct me if I am wrong on this. –  Mike Perry Jul 3 '11 at 23:36
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@Walker Bridging the DPC is just asking for problems (IMHO). One possible solution might be applying "External Bellcast Bead" just above the DPC (this will form a drip edge) and applying "External Render Stop Bead" just below the DPC (this will allow you to render a plinth from just below external ground level, up to just below the DPC), thus not actually bridging the DPC. Regardless of the rendering solution implemented you really need to address the high external ground level in relationship to the PDC. –  Mike Perry Jul 3 '11 at 23:45
    
@Mike, please make your comment into an answer, (I also thought of using a "render expansion joint" over the dpc) –  Walker Jul 4 '11 at 15:36
    
@Walker, done! please see here: diy.stackexchange.com/questions/3796/… –  Mike Perry Jul 4 '11 at 16:03
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