Insulate ceiling beneath wood floor

Old 02-25-15, 05:01 PM
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Insulate ceiling beneath wood floor

I live in michigan where the winters are pretty cold. I have a 2 story house with a unfinished basement. I have bamboo floors on much of my main level floor and I am wondering what I can do to keep them warmer in the winter. I have access to the ceiling in the basement beneath the floor. Would a reflective insulation like the one below keep the wood floor significantly warmer in the winter? Would it help with cooling in the summer?


Reflectix 16 in. x 100 ft. Double Reflective Insulation with Staple Tab
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Old 02-25-15, 05:41 PM
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Hi Dan,
We could get into a long discussion about when and where reflective barriers are beneficial, but basically you need to focus on one of two options. Either air seal and insulate that basement ceiling and ventilate the basement, or seal the basement from the outside and insulate the foundation and perimeter wood portion of the ceiling, plus air sealing. Neither is as simple as what you asked.

Tell us more about your basement and heating system.

Since your objective is warm floors, there are some reasonable steps you can take to make the entire basement warmer and reduce your heating costs. If the basement is warmer, those floors will be warmer.

Old 02-26-15, 04:19 AM
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I am responding to your question by offering a little insight into what people conceive to be a "warm" floor.

I just dealt with this yesterday in a large house with a living room over a crawl space. BTW, the floor in that room is Brazilian Cherry, a very dense, hard, wood.

The customer said that the floor is cold and wanted to insulate it. I suggested that I would prefer to insulate the poured concrete foundation and the rim joist area with closed cell foam. There are HVAC ducts in the crawl with limited insulation covering.

I explained to this customer that a floor will never be warmer than the air temperature in the room unless the floor has radiant heat or the sun is beating down on it. If your heat is set at 70 deg. and you are walking around in stocking feet you are not going to feel warmth since your body temperature is higher than 70. If you have a dense material like hers or your bamboo or tile that is also likely not going to feel warm without the benefit of the radiant heat.

The best you can do is to prevent heat loss from the foundation wall and stopping drafts that may be occurring from the rim joist and sill area. This can best be accomplished by the application of foam to those areas. That can be rigid foam or sprayed in place, they each have their benefits and drawbacks but they will serve to limit the heat loss in the crawls space or basement. Then you can add additional
heat below the floor that will be retained within the structure and provide a somewhat enhanced feeling of comfort on the floor.

The other issues to look at are related to things like wall insulation, windows, baseboard/floor joints. They all have an effect on the air movement across the floor which may be contributing to your feeling of discomfort. The house I was in has a significant number of large casement sash which need to be reviewed for the addition of a storm panel and new weatherstripping.

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