Lath walls can be load-bearing

[MatthewC]

I'm sure this is not unusual, but I think it is worth publishing the picture. Don't ever assume, just because something is covered with lath and plaster, that it is not load-bearing (viz Kirsty on Location Location).

Our two back bedrooms are separated by a lath and plaster wall, which needed to be re-plastered as the lime plaster was all crazed and had come away from the laths - huge areas moved alarmingly, and some had been patched with modern alternatives. This is the wall structure we uncovered:

Those two X frames which you can see are both made from oak beams, 4 inches by 3 inches. Each X is about 6 feet wide and 8 feet high. At the top of the central stud is a metal bolt, pointing downwards, which has a square head about 1.5 inches across. The laths are in really good condition and even the nails are still shiny, not rusted.

This is a major piece of structure and not just a simple stud wall, although at first its purpose puzzled me. There is no corresponding wall in the kitchen beneath; on the right of the picture is a major internal structural wall, about 18 inches thick, largely of squared limestone, and on the left is the external wall which is about a foot thick, in limestone rubble. After mulling this over whilst going to sleep, finally it dawned on me: I reckon this structure is holding the external wall in place, unless someone has a different idea?

Oh, and at last the roof is done and the scaffolding down - Happy Day! - see blog

Matthew
http://houseintheenchantedforest.blogspot.com/

 

[Ixia]

One of the Sarah Beeney renovation programmes showed a couple having a lath and plaster wall x-rayed, it turned out to be a supporting wall. If I remember correctly it showed a W shaped support. I've tried Googling, but can't find the details.

 

[Feltwell]

Most L&P / stud walls are not structural, but you're quite right, some can be - and not always to take vertical loads.

Without seeing & understanding the structure around it I can't say for sure, but it sounds like this wall is there to provide lateral bracing and stop any movement in your load-bearing walls at either side (which I presume are at 90 degrees to this wall). It's not holding the external wall in place as such, just stopping it from leaning by bracing it against your internal load bearing wall (and vice versa).

In most houses this isn't necessary but it depends on how the rest of the walls and the roof are arranged - the original builder may have felt there wasn't enough support in that plane and something extra was required at that point to ensure the structure's stability.

 

[middi]

Lath and plaster has nothing in common and plays no major part in " structural support" in any building , it will act as an aid to bind and stabilise a wall by default.
Lath and plaster is mainly there to separate spaces to offer privacy or insulating exterior of buildings from adverse weather conditions.
A stud wall, and this can take many forms and variations in a timber building, is consructed to support any weight above ( if required) and/or to stop any lateral movement of a building ( if required).

A central stud in a supporting wall with two opposite diagonals, or four arranged as an " X ", does the job perfectly well as per your photo. The laths may have a stabilising effect on the exterior section of the walls in order to aid the spreading effect, but correctly built the timber wall should not have to rely on laths for this.

I have come across many variations of timber wall construction and a few with " X " internal partitions, many of these were later additions to an earlier built structure and the job they appeared to do was to just divide larger " hall" shaped rooms where the added wall also served as lateral and central stabilsers for the building. An historic feature in it's own right but usually done on a budget to serve a purpose

Middi

 

[MatthewC]

it sounds like this wall is there to provide lateral bracing and stop any movement in your load-bearing walls at either side (which I presume are at 90 degrees to this wall). It's not holding the external wall in place as such, just stopping it from leaning by bracing it against your internal load bearing wall (and vice versa).

Thanks - That's what I was trying to say!

Lath and plaster has nothing in common and plays no major part in " structural support" in any building

I wasn't wanting to suggest that it did. Having seen the rotten laths in the damp ceilings above both bedrooms, that was very clear to me!

It almost seems a shame to cover up the lovely repaired laths with plaster (scratch coat next Thursday, hopefully) as I have got quite proud of how it all looks.

 

[Penners]

Of course a timber-frame wall can be load bearing. That's how timber-frame houses are built!

The method of cladding the wall is pretty irrelevant to its structural function, really. And that's what lath-and-plaster is: cladding.

 

[yamin]

The Sarah beeny one was interesting though, as apparently just the equivalent of a modern stud partition wall, anyone would have assumed it served no structural purpose at all, with a small room beyond it that they thought perfect for an en suite. After she showed them how important its structure was they decided it was better to stay dirty!

 

[FamilyWiggs]

Of course a timber-frame wall can be load bearing. That's how timber-frame houses are built!

The method of cladding the wall is pretty irrelevant to its structural function, really. And that's what lath-and-plaster is: cladding.

As ever, Penners cuts incisively through the froth and exposes the heart of the issue with clarity. Why didn't I think of that?

 

[middi]

Of course a timber-frame wall can be load bearing. That's how timber-frame houses are built!

The method of cladding the wall is pretty irrelevant to its structural function, really. And that's what lath-and-plaster is: cladding.

As ever, Penners cuts incisively through the froth and exposes the heart of the issue with clarity. Why didn't I think of that?

Exactly my view
(I am so glad that Penners translated my post :wink: )

Middi

 

[MatthewC]

Perhaps I've got this wrong. :? I thought that I had perceived in various places (like on TV, not PPUK!) a commonly held view that any stud wall (which can include lath and plaster, in my book) could be removed as it was not load bearing. Our stone-built house has what I thought was a totally non-load bearing lath and plaster wall between two bedrooms, and to my surprise I found that it was clearly a very important bit of the house's structural integrity. Consequently I thought that it might be of interest to post a picture showing the structure, so that the world might see for themselves, should they need persuading. I wasn't trying to persuade my learned friends on PPUK of the fact - I know that you know.... :roll:

 

[CatherineB]

OK so, in my ignorance, and with our plans to knock down a couple of walls of our own...
How DO you tell if a wall is load-bearing?

(without just knocking it down and finding out the hard way, of course :lol: )

 

[Penners]

any stud wall (which can include lath and plaster, in my book) could be removed as it was not load bearing.

That's generally true of any non-structural partition wall - whether it's constructed with studwork, brick, stone or shagpile carpet.

Subject, of course, to obtaining any relevant consents.

 

[Penners]

OK so, in my ignorance, and with our plans to knock down a couple of walls of our own...
How DO you tell if a wall is load-bearing?

(without just knocking it down and finding out the hard way, of course :lol: )

Well, the very first and most important principle is: if you're not sure DON'T KNOCK IT DOWN.

You have to ascertain whether the wall is part of the structure of the building, and supporting anything other than itself. If it exists purely to divide one space from another, and performs no other function, then it's probably safe to remove it. (Subject, of course, to obtaining any relevant consents.)

But I repeat: IF IN DOUBT, DON'T! Get professional advice.

 

[AMc]

OK so, in my ignorance, and with our plans to knock down a couple of walls of our own...
How DO you tell if a wall is load-bearing?

(without just knocking it down and finding out the hard way, of course :lol: )

The first obvious clues come from the direction of floorboards - assuming that IN GENERAL floorboards run at right angles to joists and joists tend to be supported at the ends by structural walls - those walls are likely to be holding up the structure of the floor.
Another good idea is to see if there is an equivalent wall upstairs/downstairs directly in line - indicating load being transmitted down into a foundation.
Go in the loft and look to see if there is evidence of the ceiling joists and roof being supported by the wall you're looking to remove - like the joist sitting on top of it.
Finally you can drill small test holes along a horizontal line to determine the spacing of the studs and if you're careful their general dimensions (as you would to put up a shelf) make some lager inspection holes to see if there are massive timbers or just what's needed to hold the wall up.

Most mortgage providers will expect you to tell them before you go knocking down walls and may object.
Your buildings insurance may also be invalid if you recklessly go ahead and your house then starts to move around because you've removed part of its skeleton.

If you're in any doubt at all then contact a structural engineer or RICS surveyor to get a professional opinion backed by professional indemnity insurance before you wield that sledgehammer.

 

[CliffordPope]

We have a lath and plaster wall supporting the ends of the exposed joists above the two rooms it separates. But the space inside the wall is filled with flat stones roughly mortared on top of each other, and the purpose of the laths seems to be to stop the stones falling out. The wall appears to have sunk by a couple of inches over the years as the horizontal timber it is built on has rotted away, and wedges have been knocked in on top to hold the joists up. Not entirely successfully, because the floor above slopes by about half an inch.

The corresponding wall above is of ordinary lath and plaster, but is offset by about two feet from the wall downstairs, and does not appear to support anything. Rather, it hangs from the underneath of timber supporting the attic floor above.

Old wallpaper turning corners give a good guide to relative movement, as does the misalignment of skirting boards. Ours seems to have been stable since I underpinned it with concrete 25 years ago.

 

[MatthewC]

Another good idea is to see if there is an equivalent wall upstairs/downstairs directly in line - indicating load being transmitted down into a foundation.
Go in the loft and look to see if there is evidence of the ceiling joists and roof being supported by the wall you're looking to remove - like the joist sitting on top of it.

Neither of these are true in the case of the structural wall pictured in my first post above. There is no wall below it, the ceiling joists are parallel to the wall and there's no roof structure on it, but it clearly wasn't built just a a partition. That was why I thought it was an useful warning.

 

[AMc]

Completely agree - my point was these are indicators not an exhaustive list of requirements which all have to be fore filled.