Render bubbling below the DPC.

**Shaun04** · 5th April 2006, 07:03 PM

Ok, my Boss built this stunning house on the water 2 years ago before i started with him (Apprentice Carpenter), and theres been some problems with the paint on the render, its started bubbling below the DPC, now we are stumped as to what the problem could be and i am eager to know what the hell is wrong as we are doing a job now that will require rendering but this one doesnt have a DPC and we dont want bubbling on this one. They, My Boss, the paint suppliers and someone else had a meeting about what could be the problem, the paunt suppliers seem to think either its to damp (########, its round the whole house) or the paint was slapped on to early, but its only happened below the DPC, thats whats got us stumped, anyway i hope someone from here knows a sollution or can come up with one relatively soon.

Thanks.

**ozwinner** · 5th April 2006, 07:20 PM

If its below the DPC its damp that is causing the problem for sure.
I have a similar problem at home with painted brickwork and bubbling below the DPC.

Al

**Tools** · 5th April 2006, 08:40 PM

I am with Al, it is moisture.Speak with someone at MAster Builders Technologies.They will probably have something to help you.

Tools

**ozwinner** · 5th April 2006, 08:49 PM

Its caused by ground salts, when the brickwork is exposed to air the salts still come to the surface of the brick but break off or are washed off by rain.
When you enclose the salts in plastic (paint) they have no where to go, so grow and bubble the paint out.

Just my observations.

Al

**woodbe** · 5th April 2006, 10:02 PM

Yep. Don't seal below the DPC unless you want to come back and do it again, and again, and again. The DPC is there for a reason...

**Shaun04** · 6th April 2006, 07:35 AM

So do you guys know of any ways to fix the problem? The DPC got sealed up with a Waterproofing solution, the water escape holes arent sealed up though.

**woodbe** · 6th April 2006, 08:29 AM

The solution is to un-waterproof it.

Below the DPC there is moisture permeating the masonry. Having water escape holes does not allow it to escape, it needs surface area to evaporate.

Maybe you can lessen it by removing any dirt and rubble that is piled up against the wall below the DPC on the inside or outside of the wall. Maybe there is a broken pipe somewhere that is accentuating the problem.

Probably 'on the water' means in a low-lying area with water nearby, and you just need to get rid of the paint seal below the DPC and replace it with something that does not create a waterproof seal.

**ozwinner** · 6th April 2006, 08:48 AM

I used this stuff before and it works ok.
http://www.techdry.com.au/rising_damp/rising.htm

I did the house we are in at the moment.

I should have gone lower as one side of the footing is 600mm above the ground.

Al

**Shaun04** · 6th April 2006, 10:43 AM

The house was built right next to a river. This flaking of paint is right around the house. I'll show my Boss that TechDry thing, thanks ozwinner and the rest for your help

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