Exterior Rendering to the ground?

[Julius]

Hello everybody, I've just joined your forum after a Google search for 'Rendering bridging damp course' brought me to your site. I read the question regarding exterior rendering and dpc with interest because my rendering at the sides and the back of the house goes right down to the ground, the front of the house has been covered with Fife stone blocks which come down roughly to where I think the dpc is and then is rendered down to a patio area which extend across the front of the house. As far as I can see the dpc has been bridged all round the house. The house was built around 1968 and so far there is no evidence of damp problems. I guess, from the comments on your forum, that I should do something about this? Any advice from anyone else who has experienced this would be very helpful.

[ultimatehandyman]

It is normal to leave a gap, but I guess it depends what it is rendered with.

Perhaps integral waterproofer was used and so the damp may not rise up it, like it would with normal render.

Have you tested the outside skin with a damp meter on a dry day?

I would guess that damp on the outer skin would only show up on the inner skin if the cavity is blocked.

[RemedialExpert]

If there is a dpc and it is being bridged by a render coat and if the ground is more than 150mm below the dpc level. you can cut a lateral slot at this level with an angle grinder. Just the disk width, to the perimeter. make sure the render coat is broken, usually an inch or so deep. sounds tricky but once the level is found a chalk line can be put around and just follow that. Then fill with a waterproof silicone mastic. This is paintable and can be an option if the more drastic course of removeing and installing a bell drip is required.
If this doesnt cure the issues internally then you can illiminate the external ground or render as a cause and address accordingly.