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Problems with cement render finishes?

Last Post 12 Jul 2009 11:57 PM by SimonD. 4 Replies.

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mibs

New Member

Posts:2

28 Nov 2006 12:40 PM

I see that a lot of people in America are having some difficulty in finding a solution to the problem of putting a cement render finish onto a SIP house. I had the same problem, but now I have found an inexpensive and fulproof method that might help.
Although I do not operate in America, my company, Modular Homes (MIBS) Spain which specializes in the SIP technology in Spain, have had a great deal of success with cement rendering the exterior of a SIPs house without the risk of any cracking or damp intrusion.
A normal cement render, especially on alternative building methods, tends to crack in the sun. This can be a particularly troublesome problem with timber frame constructions (which we have also built) because of the movement (contraction and expansion) in the timber. It was for this reason that I stopped building timber frame houses and changed to SIPs using the Kingspan TEK™ Building System.
We use a particular kind of cement particle board (similar to the size of normal plasterboards but only weighs about 2kg per m2) which is very easy to use and handle. It has a compression strength of 30 tonnes per m2, is waterproof and even provides a little extra insulation, thermal and sound. The boards, which come in a variety of thicknesses from 6mm to 50mm (we find 10mm thickness ideal for our use). The boards are made of a solid polystyrene core coated either side with a layer of netting impregnated with cement. Therefore there is no need to apply a netting for the cement to stick to. You simply apply cement render in the normal way. Once it is finished, it is completely waterproof. No wets or adhesives touch the SIPs panels (very important). The boards also have the advantage of having a very flat base on which to apply the cement render making a much flatter high class finish. Please see 2 attached photos.
In addition to this, the boards can be used to completely insulate the floors and can be very good for flat roof finishes etc.
If you would like to know more about these boards and or our methods, please feel free to contact me. [email protected].

Regards
Tim de Sanvil

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shaun_fradd User is Offline

New Member

Posts:1

10 Jul 2009 03:38 PM
how much do these boards cost? are theyu available in the uk?

Alton

Veteran Member

Posts:2157

12 Jul 2009 08:35 AM
Tim, What brand of cement board do you use?

Residential Designer & Construction Technology Consultant -- E-mail: Alton at Auburn dot Edu Use email format with @ and period . 334 826-3979

Jelly

Veteran Member

Posts:1017

12 Jul 2009 08:58 PM
This is sort of how they use Densglass in commercial construction around here. Of course the addition of cement-impregnated netting would be a big plus. In Germany they put EPS sheets on everything and apply the render (stucco) directly to it.

SimonD

Basic Member

Posts:113

12 Jul 2009 11:57 PM
The boards still have joints and seams in them. How do you treat them before the rendering to prevent cracking?

Building Designer<br>PANELfusion, LLC, Tampa, FL<br>simon@panelfusion(dot com)<br>"Metal SIP Advocate"