Wall Insulation for Laing-Easiform House with an Unfillable Cavity

Discussion in 'Eco Talk' started by Pedal Powered Plumbing, Feb 21, 2019.

  1. My house is part of a 1969 Laing-Easiform 3-storey terrace. The loft is well insulated, and the windows are double glazed, but following a survey I have been informed that it's not appropriate to fill the cavity, owing to the construction type (If anyone knows why Laing-Easiform houses shouldn't have their cavities filled, I'd be curious to learn). I want the house to be warmer, and since I'm currently renovating the place, now is the time to act.

    As I understand it, there are two options: Internal or external wall insulation. My first thought was to opt for external, but having considered it, I'm concerned that heat will escape through the unfilled cavity (which is vented at the eaves), bypassing and thereby reducing the efficacy of the external insulation. However, having tried to research it, I haven't been able to find any data on how effective external insulation is when applied to an unfilled cavity wall. Thoughts?

    Internal insulation sounds like a pain. For a start, I'd have to do it now, whereas external insulation could be done later when I have more money/greater will to live. I'd also like to avoid the mess, having to move radiators and the boiler, and losing space inside the house. I thought it was probably worth checking with you lot to see if it could be avoided.

    I get that I could save some space by removing the plaster before insulating internally, but I want it all!

    Thanks in advance.

    Benedict
     
  2. Astramax

    Astramax Super Member

    You could consider lining the interior walls with WallRock Thermal Liner, room by room as you go!
     
  3. Thanks for the suggestion Astramax. My parents have had that installed. It stops the condensation, but their house is still pretty Baltic. I'd ideally like to insulate the house to near-present building standards.
     
  4. goldenboy

    goldenboy Super Member

    Think you have zero option but to dot and dab insulated plasterboard.
     
  5. goldenboy

    goldenboy Super Member

    Is loft insulation topped up?
     
  6. Indeed yes, tip topped
     
  7. goldenboy

    goldenboy Super Member

    If thats the case and you have everything else draughtproofed etc, then its internal insulation that you need to look at.
     
  8. gas monkey

    gas monkey Well-Known Member

    come on bed
     
  9. Right4ERSS

    Right4ERSS New Member

    Good Afternoon Benedict,

    Just to provide you with some advice on why Easi-Form construction cannot be retrofitted with cavity fill.

    Easi-Form properties should not be retrofitted with insulation because (moisture can track into the property from the additional of insulation which breaches the cavity air space approx. 50 mm wide) this can lead to:
    1. Reinforcement in both skins by horizontal steel bands to window openings (which can cause problems if the concrete cover is insufficient) corroding, allowing the surface concrete to fall away in small patches and exposing rusting beneath.
    2. Wall tie failure can occur as the ties (steel not galvanized), as dampness in the now filled cavity space develops around the ties, this will encourage corrosion in a property that is over 50 years old and may already have some form of corrosion to the ties.
    3. Installation (retrofit) can be sporadic (leaving cold spots) where the material has compacted or got stuck in the cavity leading to thermal bridges internally, mould and condensation problems will then develop as a result.
    4. Many retrofitted cavity wall companies will not carry out works due to the problems mentioned as they cannot provide any guarantee to the works, there is also a risk to them if damage is caused to the structure as a result of the works, ie. being sued for damages.
    I trust that helps for more information why not check out <www.emeraldrittersurveyors.co.uk>

    Best N.J
     
  10. Rad87

    Rad87 Member

    I like this topic. Only that I've got such house as well. Great input from Right4ERSS (other than spam :) )
    I've got insulated cavity. Not sure whether it's a problem, maybe. It's rather warm I think. But I am a bloo£y foreigner and sometimes I really don't understand the way you build stuff in UK :) I would never go for internal insulation. In my opinion it's just crazy.
    I am going to install external insulation.
    Is your cavity ventilated? Have you got actual vents at the bottom? I don't have these but maybe someone rendered over in the past
    If I would be you I would obviously seek more advice but go for: close cavities at eaves, use fire socks or something similar. Pack it with loose insulation etc. Could use minimal gaps here and there just in case.
    There is a another problem and the only solution here is to remove soffit boards, bottom tiles, use over fascia vents + riffled trays and pack around eaves fully with loose insulation or maybe insualtion boards. This is because internal skin is higher than external and it's really cold in my house (I've got soffit vents so big flow of air cools them down). If you don't have vents in the soffit then maybe it will be ok.

    Silicone render over insulation will keep walls dry, house will keep them warm.
     
  11. Nermi

    Nermi New Member

    Rad87, can I have your email address to discuss it further, please?
     
  12. Tbterrybrown

    Tbterrybrown New Member

    I have one of these houses (easiform 2) and am wondering about this too. What is most likely to be the best way of insulating? Is internal insulation an issue for the steel bands/wall ties due to bring the dew point in towards the inner wall and cavity? If so what is the solution? Is external insulation the only option?
     
  13. Bob Rathbone

    Bob Rathbone Screwfix Select

    Surely, if the cavity is ventilated, condensation within it will be very limited. Most of the condensation in buildings is caused by the warm wet air inside permeating the wall structure and condensing at the dew point within the wall fabric (interstitial condensation). Proper insulation inside and a full vapour barrier on the warm side of the insulation, not broken at the first floor level, will prevent most of the warm moist air passing into the building fabric. This should be the better option as the construction of the wall is not affected or altered from original. I would go for 50 x 50 treated battens at 600 centres with insulation between, vapour barrier over and board.
     
    Ay Bee Cee likes this.

Share This Page

  1. This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
    By continuing to use this site, you are consenting to our use of cookies.
    Dismiss Notice