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Underfloor insulation on suspended floor

  • 15-12-2013 10:13pm
    #1
    AdamTatt
    Registered Users, Registered Users 2 Posts: 2 ✭


    I am just in the process of insulating a house that I recently purchased. It was built in the late 50s and so there is a couple of feet space between the ground and the ground floor. I have been investigating the thought of insulating underneath the floor but get more and confused as I go along.

    Originally I was thinking about thermal boards but then I don't know if I need to get special ones like the kooltherm k3 or will any insulated board be ok.

    By the sounds of things my other option is to have Dpm supporting rock wool insulation.

    Is there one that is better than the other. Suggestions?
    Tagged:


Comments

  • #2
    MicktheMan
    Registered Users, Registered Users 2 Posts: 2,880 ✭✭✭MicktheMan


    In my experience, the better insulation to use in this situation is rockwool supported by light netting (not dpm). Also don't forget about the airtightness of the floor (on the warm side of the insulation).


  • #3
    AdamTatt
    Registered Users, Registered Users 2 Posts: 2 ✭AdamTatt


    Cheers MicktheMan for the reply.

    Think I was using the wrong term with the Dpm. I have heard stories of people using stuff like roofing felt. What sort of netting. Any suggestions. What thickness for the rock wool would you suggests.

    As far as the air tightness of the floor goes I plan to put down a laminate floor with insulation in between.

    Just really trying to figure out what is the most economical way of doing this. To me it seems like a logical thing to do, but there is not as much info on it.


  • #4
    MicktheMan
    Registered Users, Registered Users 2 Posts: 2,880 ✭✭✭MicktheMan


    AdamTatt wrote: »
    Cheers MicktheMan for the reply.

    Think I was using the wrong term with the Dpm. I have heard stories of people using stuff like roofing felt.
    1. What sort of netting. Any suggestions.
    2. What thickness for the rock wool would you suggests.

    3. As far as the air tightness of the floor goes I plan to put down a laminate floor with insulation in between.

    1. nylon or cord netting will work
    2. Same thickness as floor joists
    3. You will still get air leakage at edges which will negate the insulation. You need to make the floor airtight wall to wall i.e. no possibility of air leaking from under the floor into the heated space above. This is achieved by laying specific air tight membrane (overlapped and sealed if necessary) over the joists sealed to the rising walls using airtight tape such that there is a continuous airtight barrier wall to wall. You then refit the floor boards and job done ready for floor covering of choice


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