What size timber for new partition walls?

[antsbradley]

Hi,

Putting partition walls into new extension, which has doubled up joists in place to take the majority of them. However one has an alcove in it so departs the joist at right angles for a few feet then turns to carry on but not over any joists.

Obviously I undersdand that I need to put timber work in to support it, both as noggins across the gaps and also running parallel between the joists, but what size timbers should I use? would somthing like 2x4" be suffiecent of does it need to be bigger? Should I use the same size among the rafters to fix the head plate to?

Many thanks,

Anthony

 

[archconsult]

The size of timber studding is relative to the height of the partition and it's intended use. Your suggested 100 x 50 (4 x 2) is generally addequate for most situations. These days most builders in normal height dwellings ie. 2.4M (8 feet) high use 68mm CS timbers.

Whatever timber you decide on however, make sure that you have it guaged. This means that they take the smallest size of timber in any batch and run it through a thicknesser so that the timbers are all the same width.

If you just use ordinary unprepared timber out of the yard it is likely that there will be a variety of widths so when you fix the plasterboard on one side the other will not be straight.

A sole and head plate should be provided and noggings between the studs where palsterboard oints occur and to help fix electrical outlets and any other items such as kitchen cupboards.

Oh and use plasterboard screws to fix the boards and insulate voids with 50mm mineral wool for sound attenuation.

Good luck

 

[antsbradley]

Hi, thanks for reply, however I suspect that I didnt explain my question very clearly, sorry

I am OK with building the actual studwork of the wall, what I am unsure of is what size timber to put between the joists below the floor and above the ceiling in the rafters to fix the head and sole plates to. Most of the length of the partition is supported by a doubled up joist under the floor, however it runs off that at right angle, then turns again to run parallel down the middle of two joists, so I need to put timberwork between the joists to support the soleplate around this alcove shape, and between the rafters to take the headplate fixings.

I already have CLS as you suggest for the actual studwork. In fact I have quite a lot spare, but I suspect that it is to small (1.5" x 3.5") to use as noggins etc between the joists to support the soleplate, but would it be ok between the rafters for the headplate, given that there is no real deflection load on that?

Thanks Anthony

 

[noseall]

don't bother. so long as the flooring material is down, i.e. floor boards then the majority load is carried sufficiently.

if you really want to, fix some 4" X 2" laid flat.

 

[archconsult]

Hiya

Yes the CLS timber for head noggings will do fine. Fix at 600 centres max - 400 better.

In teh floor I see now what you mean. The Nogging size depends on the gap between the joists which I imagine is 350mm (400 c/cs) so in fact the same noggings would most likely do especially if you doubled them up vertically since you have extra over, or put them at say 300 c/cs. the loads are not likely to amount to much relative to the size of the gap in the joists. many builders just put the sole plate straight on the chipboard but that is very poor prqactice indeed tho' common I am afraid !

If the joists are at 600 c/cs put noggings in at say 50mm smaller than the joist depth. This allows for electrical cables and pipework runs if necessary between the joists. The noggings should be slightly less than the joists anyway so as not to cause prob's with plasterbaord ceiling under.

You do not say what the floor finish comprises of. If it is 18mm chipboard
then ceratinly go for doubled noggings especially if the joists are at 600mm c/cs. If you are using 22mm boards or greater there is little problem.

 

[antsbradley]

Many thanks for your considered reply, I appreciate it; the flooring is 22mm T&G chipboard, and joists are indeed 400mm centres.

The joists are 215mm deep, so there should be plenty of room for cables and pipes under any noggins.

Given the above shall I just get some 2x4 for the floor? It would seem easier and stronger than double stacking the CLS vertically, I am presuming from what you have said that a single piece of the CLS is borderline for floor noggins in this case?

Many thanks

Anthony

 

[archconsult]

Hi

If you are going to buy additional timber for the noggings get 147 x 50 then there will be no bother at all. Cut tight between the oists and scew nail in place from both sides of the nogging. Job done.

Have fun