Oops – or, what would I do different…

… next time?

We went through all the various steps leading to our new concrete floor. Now it’s time to wind down (just a little), look back and reflect. Reflect on what went well and what I would do differently the next time. Here are our lessons learned:

Use bigger zip ties

I purchased 4 inch zip ties to tie the pex tubing to the welded wire mesh. The 4 inch zip ties were the right size, but not the right strength.

When we poured the concrete floor and dragged the heavy concrete pump hose across the floor, the 4 inch zip ties popped left and right and went flying.



I had to rush in and re-attach the pex with the much sturdier 8 inch zip ties. They are somewhat oversized, but deliver the strength that was needed.



Clean edges

The top of the bond break was meant as a guide for the finished floor elevation. While installing the vapor barrier, we extended the polyethylene sheathing above the bond break, folded it over and tagged it down. The idea was that we cut the excess off after the pour.


The problem was that we now had obscured the clean and crisp edge of the bond breaks with layers of the vapor barrier. That made it difficult to get a real nice and clean finish along the edges.


Not that this is critical, but next time I would rent again a small concrete vibrator. Same as we have used for the spread footings.

I would go around all edges and into all corners to make sure that the concrete fills into all nooks and crevices. Just pushing the concrete against the edge and into the corners didn’t quite fill all the gaps.


How to move around

We have a basement front door, which was boarded up, and a basement back door through which we moved in and out during the pour.

We started with pour from the front towards the back. Once we were done with the pour we needed to get back to the front for the troweling process, but didn’t want to step through the fresh concrete in the back.

If I would have thought about opening the basement front door, we would not have had anything to worry about.

Duh – think!

Yep, this is where I hit the off switch on my brain and it really bothers me! What is wrong in the picture below?


I went to great length to insulate the basement floor and paid great attention to the thermal break issue – just not great enough.

Now I have my cast iron sewer work sticking out of the floor and in direct contact with the concrete. Iron is a pretty good thermal conductor and has the potential to zap quite a little bit of heat our of the radiant floor slab. I should have placed a bond break around all sewer work that penetrates the floor.

This would be a none-issue if the City of Chicago would allow the use of PVC Schedule 40 or HDPE piping for underground sewers. These two materials are not be best thermal conductors and would not represent such a big energy drain.

I am seriously considering going back and add the thermal break now, although it would have been so much easier before we poured the concrete!

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.

One thought on “Oops – or, what would I do different…

  1. Wow – what an accomplishment, despite the “oops.” And lucky you noticed the thermal break issue now before you laid flooring.

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