how thick is a stud wall?

Discussion in 'Carpenters' Talk' started by Pazzaz, Apr 5, 2006.

  1. Pazzaz

    Pazzaz New Member

    sorry - sounds a bit like how longs a piece of string. but I'm trying to design my ensuite bathroom and as its a bit tight i want to know how thick the stud wall will end up being if I use 4x2 wood. I guess 4 inches plus a bit? Can you put the wood the other way so that it would only be 2 inches plus a bit?
  2. Boxer Red

    Boxer Red New Member

    Using 4x2, the wall thickness would end up being just over 5 inches thick, after screwing half inch plasterboard and skimming. I would not recommend using the other way round, 2 x 4, as you will need to insulate the wall for sound reasons, ( big fart at 7 in the morn might upset the wife!)The thicker the insulation the better! Generally, I use 3 x 2 CLS with 75mm insulation. This will reduce the thickness by an inch. Like everything else, you pay for what you get!
  3. Pazzaz

    Pazzaz New Member

    Brilliant, thanks. Hadn't even given sound a thought!
  4. jonah.

    jonah. New Member

    Boxer red is correct - sound insulation is actually required in walls around bathrooms as part of the building regulations. Dont use ordinary loft type insulation though, get sound deadening insulation. This is much more dense than thermal insulation and better at sound reduction.

    75 x 50 studs should be adequate for the job. You could use CLS timber which from memory is 68 x 38mm or something like that. The CLS usually comes straighter than ordinary softwood anyway.

    Some insulation manufacturers make a 65mm thick batt that is adequate for this purpose and fits quite neatly into the void between CLS studs

    If you go down the CLS road I would be tempted to reduce the centres of the studs to 400mm

    If things are getting really tight you could go down to 9.5mm plasterboard in stead of 12.5mm with 400mm centre studs. Allow another 3mm either side for skim plaster finishes

    Might be teaching grannie to suck eggs but remember to allow for additional noggins for fixing sanitary ware

    Cheers - Jonah
  5. trench

    trench New Member

    B/regs won't push for insulation between ensuites & bedrooms. But boxer has a point with 7am fanfare (or more likely noisy showers or WC flushes)so just go as far as you want. I would have thought a 75mm stud with 9.5mm board either side would have done. You can get proper sound quilt to use too. ISOWOOL do it.
  6. Pazzaz

    Pazzaz New Member

    Great, thanks both of you. It's not teaching granny to suck eggs at all. I've bought a house to do up to sell and I'm trying to do it more or less all on my own. Great fun, but pretty tough for a smallish, weakish girl who doesn't know quite what she's doing! Um, could I ask another question? What will be the minimum width of a door plus architrave? I think that the minimum door width is 2 and a half feet, but not too sure how much I have to allow on the sides. (This is for the ensuite too).
  7. Boxer Red

    Boxer Red New Member

    Pazza, doors come in different sizes, but a 2 foot 3 inch door should be ok. The frame should be a quarter of an inch bigger than the door unless you want to plane it down. Door frames are not as easy as you think, however if you are gonna do the studwork, then you should be ok with the frame. Agree with the 400mm centres with studwork also. The architrave is second fitting but hang the door first as you may need to tweak the frame abit to suit the door.
  8. sherlock

    sherlock New Member

    Re: how thick is a stud wall?
    Posted: Apr 6, 2006 10:55 PM Reply

    B/regs won't push for insulation between ensuites & bedrooms. But boxer has a point with 7am fanfare (or more likely noisy showers or WC flushes)so just go as far as you want. I would have thought a 75mm stud with 9.5mm board either side would have done. You can get proper sound quilt to use too. ISOWOOL do it.

    b/regs made me put in insulation, they also pushed for 12.5mm plasterboard.
  9. Boxer Red

    Boxer Red New Member

    I agree, Building regs would require that, however if LBC not involved then it's up to you. Also, LBC won't check the thickness of board after it's skimmed and they don't usually want to see it before. I'm not saying it's a good idea to bend the rules, just saying what the eyes don't see....
  10. jonah.

    jonah. New Member

    The current building regs for wall to bathroom in a new build house require 75mm minimum stud, 25mm minimum insulation (10kg/m3 density) and 12.5mm plasterboard (or equal at 10Kg/m2)

    If you dont put the insulation in you could put 2 layers of plasterboard both sides (or equal at 10Kg/m2) with joints staggered)

    These are for NEW BUILD and the local authority will take relaxations for conversion work.

    If you are doing this as a project to sell on - you will be asked by the purchasers solicitor at the time of sale if any modifications have been made. You of course dont have to say anything, but, bear in mind the installation of an en-suite is a controlled element of work that requires approval of the local authority building control. The constuction detail of the wall is imposible to confirm retrospectively.

    Cheers - Jonah
  11. jonah.

    jonah. New Member

    On the door issue - it depends really on the situation

    A 2'3" door is sufficient but some may consider it small from a re-sale point of view. Try a 2'6" wide door but in the end - if things are tight - its what ever fits!

    Allow 2mm either side of door to inside of linings, then 5mm either side of that to architraves. then the width of architrave should match the others in the room (door to Bedroom). If the door is situated in the corner of the room then ideally place a stud against the wall to fix the lining. This will allow for a small architrave with painted margin into the corner. If things are tight then just pack the lining off the wall from the corner to get it vertical. You can always trim the architrave down into the corner and around the existing skirting at the base.

    Cheers - Jonah
  12. trench

    trench New Member

    Your BCO was a bit keen. The regs don't allow him to ask for that.
    There are 3 situations where the regs relatings to sound insulation within a dwelling do not apply:
    1. Internal wall containing a door
    2. Wall seperating an en-suite from its bedroom
    3. Existing walls & floors in a building that is converted to a house.
  13. jonah.

    jonah. New Member


    You are absolutely correct - just checked the regs - doh!!

    I spend my life keeping up with these regs and they double every six months at the moment - and then I forget all about the exemptions

    Well done sir, just changed a specification / design i'm doing at the moment and saved the client a bit of money

    cheers - jonah
  14. ebanista

    ebanista New Member

    "Re: how thick is a stud wall?"

    About two short planks? :)

    Sorry,cr*p reply, but i couldn't resist. i've had a very slow day as u can tell!
  15. Pazzaz

    Pazzaz New Member

    Great. thanks all of you for your help

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