New here, please be nice, wall problems?

Discussion in 'Builders' Talk' started by Rhys jones, Dec 26, 2013.

  1. Rhys jones

    Rhys jones New Member

    Hi guys, just bought a house and it as hell of a mess when we got in there, I have taken down the stud wall I between two reception rooms and the remaining plasterboards from the exterior wall, my question is should I take down this vapour barrier and insulate the wall or just plaster board over it?? I am a DIYer and by no means a pro, please excuse the mug shot lol

    Thanks in advance

  2. tom.plum

    tom.plum Screwfix Select

    no, the vapour barrier is there for a reason, don't take it out or puncture it, and if that dividing wall was structural in any way, put a hard hat on, o_O
  3. Devil's Advocate

    Devil's Advocate Well-Known Member

    Hi Rhys (?).

    What is behind that foil? And insulation?

    I think - regardless of what else is there on the outside walls - I'd be inclined to replace with Thermal Laminate Board, which is basically plasterboard (usually 9.5mm stuff) with high-value polyurethane insulation bonded on to the back. It'll be as easy to fit as or'nary plasterboard sheets (just use longer screws), but will add a really useful extra level of insulation. Even the thinnest stuff - which has about 25mm insulation layer (so about 35mm thick in total) - will make a huge difference.
  4. Ray Retired

    Ray Retired Active Member

    Hey Rhys

    Considering the 'vapour barrier' is showing brickwork and timber in numerous places, (kinda knackered?) I'd be more than tempted to condemn it all to a skip. Replace & Insulate as suggested above.

    Hmm, and maybe rearrange the seating a tad or get a coffee table, t'will make the room muchly more homely. ;)
  5. Rhys jones

    Rhys jones New Member

    Hi guys and thanks for the replies, the dividing wall was not structural, had it checked first, the vapour barrier is knackered, it has a lot of rips/tears and holes, there is nothing at all behind the existing barrier just bare brick, I was going to go down the lines of ...putting a new barrier on, then using the plasterboard with polystyrene stuck to the back of it, or would it work out cheaper to buy the polystyrene blocks and put them in the recess between the timbers,
    vapour barrier and then normal plaster board over the top??

    I'm just a tad concerned about condensation that's all, any tips or should i just get stuck ?

    Also where would be a good place to buy these insulated boards? Struggling to find them at a descent price..

    Thanks again.
    Last edited: Dec 27, 2013
  6. Rulland

    Rulland Well-Known Member

    And you need a new hammer
    Rhys jones likes this.
  7. Sean_ork

    Sean_ork Screwfix Select

    thermal lining is very expensive if you buy the combined Pb/PU product - it also makes forming a full VCL impossible - it also limits the finish to tape and jointing, rather than a full skim (unless you don't mind a full skim of the ''wrong'' side of the Pb.

    standard foiled back Pb, with foil taped joints, overboarded (stagger the joints) with Pb is so much cheaper and easier to install - just ensure that your studwork is correctly centred for the size of boards you use, and have a supply of Pb screws of a suitable length available as you will be fixing to the studwork through the PU, so an additional 25 - 40mm length will be needed.
  8. Devil's Advocate

    Devil's Advocate Well-Known Member

    Rhys, are you DIYing?

    Then use the stuff I mentioned and ignore Sean.

    Skim the wrong side indeed...
  9. Sean_ork

    Sean_ork Screwfix Select

    which product are you recommending Mr DA ? top or bott ?

  10. joinerjohn1

    joinerjohn1 Screwfix Select

    Is Mr Ork saying you can't skim plaster board now? Whatever next? He'll be advising grannies not to clean their windows with Windolene (or teaching them how to suck eggs.) :D:D:D:D:D:D

    BTW, even Gyproc say that the boards can be fully skimmed with easyfill (but Sean will probably prove the manufacturers wrong):D:D:D:D:D
  11. Devil's Advocate

    Devil's Advocate Well-Known Member

    Hi Sean.

    I'm trying to remember the stuff I used when converting my attached garage to a living area. It had 9.5mm board, and I'm pretty sure the 25mm-ish poly layer didn't have a foil backing.

    It was also taper-edge board which made taping easy before then skimming the whole ivory lot. Which was not a problem in any sense.

    I don't actually know what you are suggesting on your post above with 2 layers of pb, the first being foil-backed. Where's the insulation? And isn't their current vapour barrier adequate - even if it does need the odd repair?

    Anyways, sod the cost for such a small area - if you want to add a goodly level of insulation in a single step, TLB is hard to beat, especially for a DIYer.
  12. Rhys jones

    Rhys jones New Member

    Yes I will be DIY-ing, and I have taken the existing vapour barrier down, it was a little worn, installed a new one and just wondering about these boards, the knauf thermal laminate boards are £18 a sheet excl vat (2400x1200x30mm) these seem a descent price...?

    Thanks again.
  13. Devil's Advocate

    Devil's Advocate Well-Known Member

    Hi Rhys.

    That's the stuff!

    Ok, I'm not saying it' gospel you should do it this way, only that I can't think of an easier and more effective way.

    I used this stuff on a single-skin block wall. All I added to the inside was 25mm Jablite (cheap polystyrene insulation) fitted in between 2x1 battens I'd screwed to the wall, and then overlaid this with the TLB. Couldn't have been easier, and it is a genuinely cosy room.

    Ideal for DIYers like myself :).

    Ok, if you don't have any other insulation on that exterior wall, this thin layer of TLB ain't going to bring it up to current standards, but - to be honest - there's little point unless you make the whole of your house air tight and up to current regs too.

    What it will do, tho', is add a very noticeable improvement, enough to make it a comfy home. Any extra insulation you add over this will only make relatively marginal improvement. Eg: Say you double the thickness of insulation, you'll only get a tiny increase in insulation value - ooh, around 5-10% improvement, I'd guess off t'top of m 'ead. Why so small? Because the first layer has done 90%+ of the work, so any extra layer can only insulate the relatively tiny sub-10% heat that's still trying to get through the first layer.

    If I were you, I think I might be tempted to first overlay the whole thing with 25mm Jablite - just pinned in place - and making sure the joins are staggered to those of the final boarding. Then your TLB over that.

    Mark out the locations of your stud uprights accurately on the ceiling and floor...

    Is that a concrete floor? Do you know what insulation in under there - if any? How old is the house?
  14. Sean_ork

    Sean_ork Screwfix Select

    based on that price I suspect you intend to use the lowest performing of the 3 options (in the Knauf Thermal Laminate) range - this has the white polystyrene bonded to it. There are a number of others who offer these products, such as Kingspan.

    Please remember that while the far better performing options (that use a phenolic insulatant) are much more expensive, they will be keeping that expensive heat on the insides far better than the cheaper version, so it is false economy not to install the best performing product - if you can't afford it now, save up until you can afford it.

    Some details of the options and comparative performance data can be viewed here.

    The option I tried to detail previously is to achieve the same result (phenolic insulation behind Pb) using the individual products. This is far cheaper than the combined bonded product and allows you to foil tape the insulation joints (for a continuous VCL) - Pb is then fixed through the insulation to the studs in the usual manner (using longer than normal Pb screws).

    Find yourself a proper builders merchants, Buildbase for example, and get them to quote for all the materials needed for the job, the more you spend the more discount you will get - and be prepared to ask for more discount. Get a few quotes and let the merchants win your custom by giving you their best price. As you've just purchase it there's a good chance you'll be doing lots of work, and spending on materials regularly, so you might find a merchant who offers you an account.
  15. Devil's Advocate

    Devil's Advocate Well-Known Member

    Rhys - do as he says^ :)
  16. Devil's Advocate

    Devil's Advocate Well-Known Member

    Sean, is the stuff in your top pic the 'white polystyrene' type? I'm pretty sure the TLB I used had phenolic (or polyurethane?) insulation, and it was a creamy colour (I think), but had no foil. Anyways, that's going back around 8 years.

    If it's cheaper to go separate layers as you suggest, then it's really no greater hassle either, so does make sense.
  17. Sean_ork

    Sean_ork Screwfix Select

    the top pic is the pure white poly type - yes the creamy product is the high performance version - I'm surprised that it had no foil, the products available today have foil on both faces (of the insulation)
  18. Devil's Advocate

    Devil's Advocate Well-Known Member

    Possibly my mind playing tricks... :oops:
  19. Sean_ork

    Sean_ork Screwfix Select

    I omitted mentioning these folks
  20. Rhys jones

    Rhys jones New Member

    Hello guys and thanks for the replies so far, really helpful, the walls are already insulated within the cavity thingy lol, looks like some sort of foil backed polystyrene, so this "extra" insulation is to make it nice an toasty, this is what I have so far, it's not easy doing it on your own!




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