FAQs Roofs

When can I install a roof membrane?
Typically, you can install a roof membrane in 3 to 7 days. In fact, the NRDCA recommends doing a nail pull test on the third day after the top coat was poured. The nail pull test criteria is 40 lbs.

Can an insulating concrete roof be patched?
Yes, an insulating concrete roof can be patched with an approved patch material i.e., cement, vermiculite, or perlite, with a latex bonder.

What R-Values are typical and how do you achieve R-Values in insulating concrete?
Typical R-Values for insulating concrete are R-19 (4 inch eps board and 2 inch fill) and R-30 (6.5 inch eps board and 2 inch fill).By encapsulating eps board in the LWIC system, for higher R-Values you can increase the thickness of the eps board to 8 or 10 inches even though the U.L. fire directory only acknowledges a maximum of 8 inch eps board.

What are the advantages to a LWIC roof system?
With an insulating concrete roof system, eps board is encapsulated in the fill and thus is protected by a minimum 2 inch top coat of insulating concrete. It will not deteriorate like other roofing systems that have roof membranes attached directly to the rigid board, thus causing deterioration due to heat. The insulating concrete roof system will also stand the test of time and when a new roof membrane is to be installed, you do not have to start from scratch -- you can typically reinstall a roof membrane over the insulating concrete roof.This is not commonplace with other roofing systems.

How resistant to weather is LWIC?
After a LWIC roof deck has been poured and set up, it is highly resistant to weather. In fact, water actually helps the LWIC system cure out and strengthen.

What types of roofing systems can be installed over LWIC?
Built-up roofing, Modified Bitumen, single ply membranes, and some metal roofing systems.

Are control joints needed for thermal movement in a LWIC system?
No.

Is venting required in a LWIC system?
Venting to relieve vapor pressure is dependent upon the structural substrate, the specific LWIC and/or the membrane manufacturer.

Is LWIC a "green" product?
Yes.

How high can you pump LWIC?
550 feet.