Lightweight concrete

I ran across your Web page while looking up information on "lightweight concrete."

I am building a home outside Healy, Alaska near Denali National Park. I would like to pour a self-leveling concrete type product approximately 1.5" deep in my home for in-floor hydronic heating coils. Wirsbo cross linked poly with an oxygen diffusion barrier was what I have planned to run as the tubing.

My problem is I may be not have enough strength in the current joists to support the dead load of concrete. I am interested in any products available that will be suitable for this application and the correct formula for figuring the load on the floor joists.

If you would point me in the right direction, I would appreciate it.

By the way, I thought your Web page was very forward thinking.
It sounds like you need to get a structural engineer to look at the original design of these joists and calculate the extra capacity required for the concrete. This is a relatively simple calculation when you have the plans - but not something you can do by e-mail.

Good luck with your project.