1. Welcome Hearth.com Guests and Visitors - Please enjoy our forums!
    Hearth.com GOLD Sponsors who help bring the site content to you:
    Hearthstone Soapstone and Cast-Iron stoves( Wood, Gas or Pellet Stoves and Inserts)
    Caluwe - Passion for Fire and Water ( Pellet and Wood Hydronic and Space Heating)

Insulation under the floor

Post in 'DIY and General non-hearth advice' started by BrowningBAR, Jan 27, 2013.

  1. BrowningBAR

    BrowningBAR Minister of Fire

    Joined:
    Jul 22, 2008
    Messages:
    7,607
    Loc:
    Doylestown, PA
    I have an old home. Super old home. I have no basement or crawl space. I do not have any real access to under the flooring unless I pull up the flooring.

    My problem/hurdle is that I have cold air coming up from the floor. I can feel air leaks in several areas of the floor. There are some spots that will produce surface temps below 40 degrees on cold days.

    I feel this is one of the main areas I need to tackle in order to decrease my heat loss. Does anyone have any suggestions as to what needs to be done to correct this problem.

    General info:
    • All flooring is wood flooring.
    • Carpeting is not an option. (combination of cost and old carpeting was removed, lots of time spent on refinishing the wood flooring)
    • The flooring is old. The kitchen flooring is quite possible the original wood flooring.

    Helpful Sponsor Ads!





  2. Trilifter7

    Trilifter7 Feeling the Heat

    Joined:
    Oct 19, 2012
    Messages:
    452
    Loc:
    Beavercreek Ohio
    I am curious about this as well. I have an older home with a crawl space and my wood and tile floors are not insulated underneath either. I regularly see 40-45 degree temps on my floors. I don't have any draft coming from mine like you have but it is def a big heat loss. I am very interested in what anyone recommends here.
    BrowningBAR likes this.
  3. BrowningBAR

    BrowningBAR Minister of Fire

    Joined:
    Jul 22, 2008
    Messages:
    7,607
    Loc:
    Doylestown, PA
    I'm guessing I am going to need to pull up some of the flooring, but I want to make sure the solution is the correct one and I won't have to revisit this problem.
  4. Hearth Mistress

    Hearth Mistress Minister of Fire

    Joined:
    Jan 24, 2012
    Messages:
    852
    Loc:
    Pt Pleasant, PA (SE PA)
    Same thing here too, random width original wood floors, 1860's floor over dirt, literally, in living room, floor in kitchen, from 1920's same thing. No foundation, crawl space, it's a pointed stone bank barn so every nook and cranny leaks. I have a lifetime supply of silicone and foam insulation but have yet to have anyone ever come up with anything for the floors other than carpet or tearing up the floor and starting over.
    BrowningBAR likes this.
  5. BrowningBAR

    BrowningBAR Minister of Fire

    Joined:
    Jul 22, 2008
    Messages:
    7,607
    Loc:
    Doylestown, PA
    Same exact thing for me. Pull up the flooring I have dirt and rock. If I can find a way to seal the parameter under the flooring I think that will cut down on the incoming air. But I have no idea if this is correct or what materials I need to use.

    But, If we can find a solution to this, I think it would help both of us out. I feel this is one of my bigger heat losses at the moment. This and the attic. The attic I can plan for. The underneath is a huge question mark.
  6. Hearth Mistress

    Hearth Mistress Minister of Fire

    Joined:
    Jan 24, 2012
    Messages:
    852
    Loc:
    Pt Pleasant, PA (SE PA)
    We have an engineer scheduled to come out in two weeks to make some recommendations for the repairs we are about to get done thanks to Sandy. The house has been deemed structurally sound, but we want to maintain the original "feel" of the house with some upgraded things, like tyvek wrap such. I will pick his brain to see what he thinks. I wonder if there is a tyvek type material or subflooring to insulate old floors. I've actually taken linen cloth and shoved it in the bigger cracks with a screw driver. I got that idea after watching a shop deck be restored in the history channel (minus the pitch tar of course)

    I've saved this thread so I'll post what the engineer says.
    Pallet Pete likes this.
  7. Trilifter7

    Trilifter7 Feeling the Heat

    Joined:
    Oct 19, 2012
    Messages:
    452
    Loc:
    Beavercreek Ohio
  8. BrowningBAR

    BrowningBAR Minister of Fire

    Joined:
    Jul 22, 2008
    Messages:
    7,607
    Loc:
    Doylestown, PA
    If the engineer seems to be respectable and offers good solutions, send me his info after you've spoken with him.

    I need to know how much cost I need to plan for to get this issue solved, so I might as well have him come out here now than later.
  9. BrowningBAR

    BrowningBAR Minister of Fire

    Joined:
    Jul 22, 2008
    Messages:
    7,607
    Loc:
    Doylestown, PA
  10. Highbeam

    Highbeam Minister of Fire

    Joined:
    Dec 28, 2006
    Messages:
    9,106
    Loc:
    base of Mt. Rainier on the wet side, WA
    My wood subfloor is made of 1.5" thick t&G boards so not air tight. In the early 1960s the method of construction was to cover the decking boards with tar paper and then install the hardwood floors or underlayment for carpet on top of that. The tar paper provides the air seal.
  11. BrowningBAR

    BrowningBAR Minister of Fire

    Joined:
    Jul 22, 2008
    Messages:
    7,607
    Loc:
    Doylestown, PA
    For Mistress and myself, when you pull up the wood floor, there is no sub-flooring. Just large, hand carved beams, rock, and dirt.
  12. Highbeam

    Highbeam Minister of Fire

    Joined:
    Dec 28, 2006
    Messages:
    9,106
    Loc:
    base of Mt. Rainier on the wet side, WA
    So you're walking on what more modern builders call "subfloor"? One layer of wood and then dirt?
  13. BrowningBAR

    BrowningBAR Minister of Fire

    Joined:
    Jul 22, 2008
    Messages:
    7,607
    Loc:
    Doylestown, PA
    Yep.
  14. ScotO

    ScotO Guest

    I agree, that is a great post. I'm glad I came into this forum tonight, I have a similar situation in the fireplace room. It's a crawlspace as well, and I am definately going to do something like this to it. Possibly this summer. I may just bite the bullet and pay to have it done if someone local is set up to do it.
  15. begreen

    begreen Mooderator Staff Member

    Joined:
    Nov 18, 2005
    Messages:
    48,229
    Loc:
    South Puget Sound, WA
    Was this part of the house a cow barn at one time in the past?
  16. BrowningBAR

    BrowningBAR Minister of Fire

    Joined:
    Jul 22, 2008
    Messages:
    7,607
    Loc:
    Doylestown, PA
    Unless every room was a cow barn, I would have to say no. Every room on the ground floor is like this (kitchen, dining room, living room, Summer kitchen/den).

    Each room has a part of the floor that can hit the low 40s to upper 30s. I'm saying this is one of the key areas that needs to be address in terms of my heat loss issue. Even before windows and doors.
  17. begreen

    begreen Mooderator Staff Member

    Joined:
    Nov 18, 2005
    Messages:
    48,229
    Loc:
    South Puget Sound, WA
    The reason I ask it that my folks looked at a stone building like your home in CT. The floors were similar and it's history was a cowbarn. It was a long large galley of a space that got subdivided into rooms.

    Have you considered putting down an air seal, insulation and a top flooring? It sounds like that could make a nice difference.
  18. BrowningBAR

    BrowningBAR Minister of Fire

    Joined:
    Jul 22, 2008
    Messages:
    7,607
    Loc:
    Doylestown, PA
    Could you point me in the direction as to what you mean by an "air seal?"

    And by top flooring, do you mean like something that highbeam was talking about? A subfloor with tar paper on top then the hardwood flooring?
  19. Bret Chase

    Bret Chase Minister of Fire

    Joined:
    Jan 15, 2013
    Messages:
    648
    Loc:
    Maine
    that must be an ooooooold house... mine was built in 1865... and I've got 1 1/8" pine subfloors and 1" pitch pine flooring.... when I pulled out the carpet in the living room there was *real* linoleum and newspapers dating to 1962 under the carpet....
  20. BrowningBAR

    BrowningBAR Minister of Fire

    Joined:
    Jul 22, 2008
    Messages:
    7,607
    Loc:
    Doylestown, PA
    House dates back to 1741.
    ScotO likes this.
  21. boatboy63

    boatboy63 Member

    Joined:
    Feb 6, 2010
    Messages:
    188
    Loc:
    Northeastern TN
    We are also in a similar situation. The main part of our house was built in the 1890's. There is enough crawlspace clearance to reach about half way back. We attempted to put fiberglass batts under there several years ago, but it didn't work the best. Most of the floor joists range from 12" - 27" which throws the standards out the window. The joists are all nailed into beams under the house and they sit on stone pillars. The main part of the house does not have a foundation like most newer houses do. Most of these batts have now fell and are laying on the dirt. I gave up on it.

    I did do a remodel of a bathroom floor a few years ago that really helped out. That room used to be the coldest in the house but now can be heated much easier. The floor is at least 30 degrees warmer. I ended up pulling cabinets, sink, toilet, washer, and dryer out. The floor had alot of wave to it and was nowhere near level. Floor had the 12" peel and stick tiles on it. I peeled them from the higher areas and put those down on the lower areas to level it out. Next, I took 7/16" OSB and laid on top of this then caulked in all the joints of the OSB. I then took the thin foam roll used for installing beneath the laminate and laid it down on the OSB. I then cut and installed new laminate flooring and put all fixtures back in there. I swear, it made more difference than I would have ever dreamed of. If you had any plans of installing carpet on your floors, you could do as I did with the OSB and see a definite difference. I can only guess it is because of the glue in the OSB along with the foam acting as insulators.

    Trust me...I know your pain when it comes to trying to insulate a 120 + year old house. When we first inherited it in 2000, we nearly froze to death. In the next few years, we even went so far as to pull off the vinyl siding that was put on the house in 1995 and the masonite siding that was put on in the early 80's. We put insulation anywhere in the walls that we could and even nailed 2"x2" lumber to the old wall studs and added more insulation in those cavities. I then covered them with 7/16" OSB and Tyvek, then put the vinyl siding back up. I even installed thermopane windows. Before doing all this, the house was so drafty, you could even see curtains move during high winds. It is much easier to heat now and it doesn't have the hot/cold spots all thru the house like it used to. It stil would not compare to a newer house, but it is about as good as it gets.
    ScotO and BrowningBAR like this.
  22. begreen

    begreen Mooderator Staff Member

    Joined:
    Nov 18, 2005
    Messages:
    48,229
    Loc:
    South Puget Sound, WA
    Yes, a layer of roofing felt or similar air barrier is what I meant. Then top it with flooring. For more insulation you could put foam sheeting or Durock NextGen underlayment down before the top flooring. There are some products out there meant for basement floors that have insulation built in and a laminate flooring on top. Or use cork as a flooring. It's warm and quite attractive.
  23. Bret Chase

    Bret Chase Minister of Fire

    Joined:
    Jan 15, 2013
    Messages:
    648
    Loc:
    Maine
    15# felt is an old school air seal for a floor.. that being said, when I pull up the hard pine flooring in my dining room (which has been COMPLETELY worn through in spots) I will be laying the same 15# felt under my new 3/4UL plywood... which will eventually be covered by laminate..
  24. jharkin

    jharkin Minister of Fire

    Joined:
    Oct 21, 2009
    Messages:
    3,322
    Loc:
    Holliston, MA USA
    The use of subflooring or not also depends on the region and how wealthy the builders were.

    My house, depending on what evidence you believe was built somewhere between 1790 and 1830. On my first floor I have inch thick tongue and groove board subfloor, some of which are over 30 inches wide (pointing to a pre -1800 date), topped with 5/8 T&G pine finish floor, that are fairly uniform 12 in wide and are face nailed with machine cut nails (pointing to post 1810). This all sits on vertical sawmill cut 3x5 (true) joists mortised into hand hewn 6x7 carrying beams that rest on unfinished tree trunks for posts in the basement. What we don't know is if the finish floor is original or replaced. We also don't know if the very wide subfloor boards are original or where just reclaimed from some older structure.

    In contrast, upstairs was originally unfinished attic and has a only single layer of rough 5/8 T&G boards of varying widths (some quite wide like the downstairs subfloor).


    I have been in museum houses that are older that have subfloors, and I have visited houses that are younger that don't. There is a lot of variation in the late 1700s/early 1800s. I think when you get back to pre-1700 though you pretty much never see a subfloor.
  25. BrowningBAR

    BrowningBAR Minister of Fire

    Joined:
    Jul 22, 2008
    Messages:
    7,607
    Loc:
    Doylestown, PA
    Right now I am looking into expansion foam to spray in under the flooring.

Share This Page