Comments on: Rastra or Durisol? Eco-Alternatives for Construction

By: Dean McAlister

Dean McAlister — Sat, 21 Aug 2010 17:50:23 +0000

We have a 10 year old RASTRA home that was built with a traditional tree coat stucco finish. Since construction we have had problems with water at the floor level after a hard rain. The water appears to be moving behind the stucco and passing through to the inside when it hits the floor slab. Since we have colored plaster interior walls this is a real problem. Short of painting the outside of the house, has anyone found a solution to this type of problem? We hate to give up our hard troweled stucco finish fo a painted surface.

By: louis abrams

louis abrams — Fri, 30 Apr 2010 01:10:59 +0000

we’re about to purchase a rastra=made home in colorado and since it’s a major investment for us we are extremely interested in knowing, with a five-year-old home, how a buyer can determine if it was “done right” or not? this seems to be the burning issue from what we are reading, whether or not the installation of rastra block was done propertly in order to manage water issues–and how can one tell ‘afterwards’ please?

By: louis abrams

louis abrams — Fri, 30 Apr 2010 01:10:00 +0000

By: louis abrams

louis abrams — Fri, 30 Apr 2010 01:10:00 +0000

By: Jon McLelland

Jon McLelland — Thu, 25 Feb 2010 02:36:58 +0000

Thanks for all the comments here. I’m an architect and have two Rastra houses going right now, one nearly complete and one just coming out of the ground. It’s a system I’ve wanted to work with for a long time, and so far it seems to be all I’d hoped it would. We’ve used the 12″ blocks, and the walls are amazingly stout. There’s a very noticeable temperature and acoustic difference between inside and outside, even without windows and doors in place. Because it’s a new system where I am (in Alabama), there’s still a fair amount of nervousness among builders about how to deal with it. Our builder still isn’t really satisfied with the water-management advice we’ve gotten so far. Anybody else out there who’s used it and can recommend solutions, I’d love to hear from you.

By: Jon McLelland

Jon McLelland — Thu, 25 Feb 2010 02:36:00 +0000

By: Jon McLelland

Jon McLelland — Thu, 25 Feb 2010 02:36:00 +0000

By: John Neville

John Neville — Wed, 03 Feb 2010 20:31:55 +0000

I built a home in Sedona, AZ with Rastra Block in 2003-4. I had the Rastra people put up the walls to be sure things were done right – they weren’t. The home works fine in the hot months – we have no AC – and not as great in the cold. Oriented for passive solar gain, the south walls warm up nicely during the winter. This warming also causes expansion and contraction issues with the 30-40 degree temperature drop over night and the rapid cooling that takes place. We have cracks. Also, the north walls never warm up. There is not enough insulation value in Rastra for the wall to function without the thermal mass of the concrete. In the north walls, the thermal mass never functions. Cold north walls.
Also there are serious issues with water infiltration. Rastra is porous and allows water to pass through easily. In driving rains, water comes into the walls. Some flows down the outside of the building taking lime and other materials from the stucco across the windows – a real pain to clean. Some water flows inside the home when the water hits a window frame and is redirected. If you use Rastra, you have to make sure water cannot get into the walls – use a water barrier – which we did not. Treat the building like a stick building – waterproof anything that comes in contact with soil – keep water away from the walls, if possible – do NOT seal the walls – allow the walls to breathe to release any water vapor that collects from the inside or outside – but keep water away from the walls. If you are really considering ICF construction, you may want to look into the closed cell forms which do not allow water to pass.

By: John Neville

John Neville — Wed, 03 Feb 2010 20:31:00 +0000

By: John Neville

John Neville — Wed, 03 Feb 2010 20:31:00 +0000