Rastra blocks

[kvilletom]

I have been on the Castleblock web site which then takes you to the Rastra block section. At that point in the site it appears it is all about SIP's. Is there anyone who does actually build with the foam forms that are filled with concrete?
Mahalo

[Rob Tucker]

Castleblock is my company. The Rastra link takes you to a Rastra page which is an ICF (insulated concrete form) product. Our other wall system and our roof system are SIP (structural insulated panels).

There is an ICF job going on at this time. My own home is built with ICF as are, by way of example, the smallest home we've done and the largest.

Please, call me if you have any more questions.

[peteadams]

We built a 16' wall that supports a second floor with the Rastra blocks. They are very easy to use. The blocks are about 15" tall, 10" wide and come in 7' lengths. Very heavy but they are easily cut. They are formed of a mix of styrofoam and cement with 6" vertical cores every 15" and half cores on top and bottom to create a horizontal full core when they are stacked. The block cores are initially placed on vertical rebar tied into the foundation. The blocks are plumbed and then glued together (staggering the joints and aligning the cores) with a polyurethane foam and horizontal rebar is placed during stacking. The vertical rebar is placed when stacking is complete. Finally concrete is pumped into the vertical cores from the top. The main thing we learned was that the concrete needs to be fluid enough to easily fill the cores without a lot of rodding. What ends up happening is that the concrete forms a rectangular grid inside the forms creating a very strong wall using not that much concrete. Finish coatings go directly on the forms. We used a mortar and vermiculite mix but wallboard compound or whatever could be used on interiors. No termite worries. Rob could add a lot more I'm sure.

[unknownjulie]

Do you have to put the rastra blocks on a concrete footer here?

[Rob Tucker]

They do require a footing.

[PauHana]

How much does one of these blocks cost ?