I am looking to renovate a 1950 slab on grade w old, but still working radiant system.

I am looking to renovate a 1950 slab on grade w old, but still working radiant system. We are planning on going over the slab with Warmboard R and then engineered flooring – how much additional height will this add approximately? Also, we have a combi boiler (purchased February this year) – can we use this combi boiler with the Warmboard R panels?

Yes. You can use your combi boiler. Shouldn’t be a problem at all. As for additional floor heights – the “R” panel is 13/16″ (roughly 7/8″) thick. You can install the engineered flooring you’ve chosen directly over the Warmboard panels – so just add that thickness and you’ll have your answer. Feel free to call with any questions – 1.800.556.0595