Packing it down

We got done with our little bump in the task list. The limestone is back in place under the windows, and it’s now time to get back on schedule, which means putting the finishing touch to the ¾ inch aggregate base.

I rented a small 140 pound plate tamper to compact the recycled stone base. Like I expected, it put a smooth finish to the base.

Before I can install the rigid foam board insulation, there is one more detail on the spread footings that I have to take care of. It is about moisture management.

spread-footing-damp-proof

I need to put a damp proof layer (or vapor barrier) over the spread footings. It prevents moisture from wicking up from the ground into the spread footing pedestal, keeping the basement floor dry.

Now I am ready to get going with the insulation.

About Marcus de la fleur

Marcus is a Registered Landscape Architect with a horticultural degree from the School of Horticulture at the Royal Botanic Gardens, Kew, and a Masters in Landscape Architecture from the University of Sheffield, UK. He developed a landscape based sustainable pilot project at 168 Elm Ave. in 2002, and has expanded his skill set to building science. Starting in 2009, Marcus applied the newly acquired expertise to the deep energy retrofit of his 100+ year old home in Chicago.

2 thoughts on “Packing it down

  1. Dear Marcus,

    Did you use the same vapor barrier (polyethylene sheathing) over the footing at this step as the one used between the isolation and the concrete slab? May I ask what is the size of the footing barrier? Is it larger than the footing area or smaller?
    I notice that the perimeter around the footing has a smoother surface compare to the rest of the aggregate layer. What is that?

    Thank you

  2. I used 90 pound rolled roofing as a vapor barrier between the footing and the footing pedestal, but a polyethylene sheet would have done as well. The vapor barrier should be larger than the footing pedestal. Because the 90 pound rolled roofing came on 36″ roles, I cut the vapor barrier piece to 36″ by 36″, which is quite a little bit larger than the pedestal. You could also cover the whole footing with a vapor barrier.

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