Q&A: A Forum for Green Building Experts and Beginners

Hi...is there a preference between pink and blue XPS foam board to be used under slab?

...and any drawbacks to using EPS in place of the XPS foam?

Thanks!

We need a new driveway and would like it to help with drainage problems. We sit at the bottom of a hill and have a big roof. The old drive slopes and has inlets and subterranean pipes to direct water from hill and downs spouts to street. The underlying soil is clay and I mean clay, as in the clay that is used to make pottery. I don't think permeable pavers would be of any use here as there is very limited percolation into the clay. Am I thinking correctly and if so what would be a good material to use to make the driveway?

Thanks

If all plumbing lines are within the envelope, and a recirculating pump is installed, what might the payback period be for insulating PEX hot water lines?

Because the advantage of PEX is that the pipes are easily curved around obstacles etc., I bet insulation coverage wouldn't be more than 90% in even careful installations.

In any case, insulation would serve no purpose whenever the wait between uses exceeded a couple of hours, no?

Is this one of those cases where the money would be better spent on more insulation elsewhere?

We're designing a 3500 sq. ft. new home in Southern California, including a kitchen with a professional range that includes a BBQ grill unit. We've had one before, we used it 4-5 nights a week so it is essential for our kitchen, but they do produce a fair amount of heat and smoke when the grill is on high. So a professional exhaust hood is necessary, and the one we're installing will draft 900 CFM on its highest speed. With new construction standards (Title 24 in California), that amount of exhaust necessitates make up air.