Unusual stud wall

[andsally]

Can anyone help with this please?

Want to run pipework inside lath and plaster stud wall and place new cold water tank in loft. Stud wall supported by brick supporting wall below.

After a bit of poking about and removing small areas of plaster, realised that there appears to be no horizontal noggins in studwork. Rather, it has two diagonal studs; the centre stud is the only full-length one in the frame. All the other uprights were fixed AFTER the diagonals. A 4x2 roof prop rests on the centre of the stud header.

As it now stands, I won't be able to get jointless pipes into loft without drilling through a diagonal stud and am now uncertain about structural strength of studwork upon which the tank will rest.

Should I be thinking about removing diagonals and replacing with full-length vertical studs with plenty of noggins?

Below is a scale plan and section.
Thanks

View media item 8582

 

[stuart45]

This is either a braced partition or a trussed partition. The diagonal is an important timber which helps add stability to the wall and transfers the loading above to the cross walls. A trussed partition is self supporting and can take the floor below's weight. It was often used in old houses with a large open space such as a ballroom beneath.
I wouldn't remove the diagonals without checking with an SE.

 

[Shytalkz]

The diagonals serve a structural purpose. However, rather than replacing the wall completely, clad one side with 9.5mm ply, fixed to the studs to the sides of the sheet at 150 centres and 300 centres to the intermediate studs, with 65mm long screws, ensuring that the top and bottom of the sheet are also fixed to noggins. Boards and hence face grain should run horizontally. Stagger the vertical joints.

Then you can go chopping into the diagonals.

 

[^woody^]

How do these walls perform in terms of loading?

Do they have an even distribution of the wall load along its length, or is the wall load (and the load it supports) transferred to the bottom corners?

Basically would a wall like this need a double joist, like a traditional stud wall would, or a beam in the floor, or are they totally load bearing?

 

[noseall]

why not build a faux stud wall or a trunking port in front of the existing and leave the entire wall, well alone.

 

[stuart45]

woody
A trussed partition wall is self supporting. The diagonal struts are in compression and transfer any load above to the cross walls. In the centre should be a steel rod in tension bolted to the top and bottom beams of the stud wall. This can also support the floor below without the need for a load bearing wall underneath. It is in effect a load bearing beam.

 

[Shytalkz]

Now Woody, if you'd stayed awake when the lecturer was on about truss analogies, you'd have remembered that

 

[^woody^]

Damn. I thought it said "flesh allergies" on the semester guide, and thought it was a boring H&S lecture so I gave it a miss.

It's OK though, I'll look it up in my Chudley bible

 

[Shytalkz]

Did they have H&S lectures back in those days when you were a lad, Woodster?

 

[andsally]

Hi guys

Thanks for replies so far. It has given me much to think about and I certainly do not intend hacking away at studs!

I have just posted two new images. Have amended plan slightly to show position of diagonals to centre upright. The grey shaded areas are brick walls that continue through 2 stories to foundations.

The photo shows loft above, with a line marking position of wall stud wall below. The horizonal beam between rafters appears to be a ridge board for the (original) dormer windows to left and right. The house was built about 1903.

I still can't get my head around the load-bearing properties of this particular partition. If there was another trussed partition directly below I could understand it.

In terms of the load upon it, there is the point load of the prop supporting the ridge board. Also, the partition serves to support 4x2 ceiling joists, either at the middle or ends of spans.

At the moment, in this paricular instance, I still can't see why a standard stud wall would suffice.

The idea of building a faux stud wall is looking appealing!

View media item 8684 View media item 8685

 

[Shytalkz]

These types of stud "beam" were often used because there wasn't a partition below it on the ground floor: it has diagonals in it to make it act like a deep beam. The diagonals take the point load from the prop as a compressive load to the bearings at floor level; they are (hopefully)stopped from moving outwards either by the bottom plate connection, or by buttressing by the walls. Works in a similar way as a plybox beam, ie a storey height beam, only they didn't have ply when that was built, else they'd have used that.

However, given that this seems to sit straight on a masonry wall below, there is no real need for it to act as a beam, although direct load from the roof prop onto a single stud might be too great a load, hence the reason why they used diagonals, rather than putting multiple studs in under the point load. At the very least, it halved the axial compression that would be applied to a single vertical stud and the infill studs above and below give it restraint against buckling.

 

[^woody^]

But what is that timber doing in the loft?

Its not a purlin, and if it's a collar, then it does not need a prop

 

[Shytalkz]

FIIK, I didn't design it!

 

[andsally]

Alas, can't build faux stud wall as there are door frames either side on the adjacent walls

 

[noseall]

faux stud wall plus new door linings.