Asked on Jan 20, 2018

Can you insulate under a porch floor

Katy Kleymeyer
by Katy Kleymeyer
We have enclosed our back patio into a sunroom. The old deck has now a tile floor. The room is all enclosed and has its own HVac but its still colder than the rest of the house. Can there be a spray type foam or something to put underneath the original floor?

  8 answers
  • 10v32354899 10v32354899 on Jan 20, 2018

    If you can get underneath therefore e, I would try mounting some R35 Pink insulation boards.

  • Russbow Russbow on Jan 20, 2018

    Under and over. Have or can you insulate the ceiling???, Do you have access under it, then yes you can insulate. You have not said where you live, so the R value of either would depend on where you live.

    • Katy Kleymeyer Katy Kleymeyer on Jan 20, 2018

      Yes the ceiling has insulation. The guy who enclosed this porch did put some of that pink insulation under but we have neihgbors who have cats and they have gotten underneath and messed some of it up. There is a gap between the ground and porch but it’s small. I have put up lattice to prevent critters from coming in but not successfully.

  • V Smith V Smith on Jan 20, 2018

    There is spray foam insulation, but I believe it is a professional install and somewhat costly. If your floor joist are 16 inches on center you can easily install bat insulation, that is assuming you can get to the underside. If you go with bat insulation I suggest you put some nails in the underside of the joists and lace the insulation in place with wire. Or you can finish off the underside with vinyl soffit siding. If you buy insulation with a vapor barrier make sure that side goes toward the room.

    • Rebecca rubin Rebecca rubin on Aug 15, 2020

      While costly one benefit to spray foam is it helps deter insects and critters from nesting in it, unlike batts.

  • Suellen Hintz Suellen Hintz on Jan 20, 2018

    Patio usually is a term used when hardscape is on the ground but porch usually is raised above ground level. If the porch is wood you can insulate from underneath but if it's concrete you can't. Heating installed before tiling would have been a nice solution.

    • Katy Kleymeyer Katy Kleymeyer on Jan 20, 2018

      It was our back porch (wooden and off the ground). The guy who enclosed the porch for us did insulate the ceiling and did lay insulation underneath, but neighbors cats have gotten underneath and made a mess. I have put up lattice to enclose the sides but they still get underneath, which really drives my dogs crazy. There’s a space between the ground and under the original porch but it’s small and really tight as you go away from the house

  • Joy30150932 Joy30150932 on Jan 20, 2018

    You can try to have blown in insulation put into that location if it is low to the ground. If you can get underneath install the fiberglass insulation and then staple a 4-6 mil plastic to the floor joists over the insulation.

  • Sharon Sharon on Jan 20, 2018

    I think I would get some rigid foam insulation, I like the foil back kind, cut an put between the joists. You may need to dig an opening at the end where the joists end, so you can slide the insulation pieces in after measuring and cutting so they are firmly stuck in.

    Then I would get some rigid wire screen the height of the opening plus 3-4", and the length all the way around, and a couple inches extra to fasten to the foundation. Dig down about 3-4" next to the porch and insert your wire into the ground as you roll out along porch footing and stapling to footing... and back fill the trench as you go. Remember to leave a flange at each end to fasten to the foundation.

  • Suellen Hintz Suellen Hintz on Jan 20, 2018

    You can insulate underneath, it sounds. Talk to a contractor or handyman to see which they think would be better, keeping in mind they may say regular insulation so they get the work, but spray might be easier, if a company will take that small a job. By laid insulation, do you mean heavy plastic sheeting on the ground or insulation placed up against the wooden porch? Consider if enclosing the under area with brick, stone or something solid would help or not with the temp while also keeping the cats out. Nothing worse than a cold room. Are you up for lots of area rugs or w-t-w carpet?

  • 2dogal 2dogal on Jan 20, 2018

    Please look into encapsulating the area under your sunroom. That is the best for insulating.