Noticed this today, what to do

[Marty76]

I was told by a builder that I could remove the ply as it’s not a load bearing material. I didn’t touch the vertical beams but I did remove the structure of the old window ledge (pic attached) and removed the insulation which was behind red plastic sheeting. The plan was to plaster bard around the beams and plaster over the old brick wall just to open the room out a bit.

 

[bernardgreen]

I was told by a builder that I could remove the ply as it’s not a load bearing material.

Sometimes plywood is a structural component of a timber frame. The plywood does not bear any load but does provide the essential diagonal bracing for the timber framework it is attached to.

 

[Marty76]

So do you believe me removing some of this has caused this issue?
If so what next?

 

[bernardgreen]

So do you believe me removing some of this has caused this issue?

It may have added to the problem. Without actually being on site and in the roof space to see how the timber panels were constructed it impossible to give a definate answer.

Being pedantic the construction is almost certainly timber panel and not timber frame. Tudor houses with posts from ground to roof are examples of timber frame construction.

Are there any diagonal braces in the roof ?

Are there tie beams at the bottom of the rafters to stop them spreading if the panel(s) supporting them fail.

If the green panels become damaged or become detached from each other ( orange dots ) then they can move apart ( orange arrows ) and the bottom ends of the rafters will move with them. A tie beam ( red beam ) between the ends of the rafter will prevent the roof spreading if the panel(s) fail.

 

[Doggit]

I can now see the small corner of the window in the first picture, but I still don't think that that's the cause, but yes, the structural panels being removed may have caused issues. But as the movement is further up the wall, it may well be that somethings gone wrong with the panels/wall ties in the roof space.

But I have no experience of this type of construction, so it's speculation on my part.

 

[wessex101]

I was told by a builder that I could remove the ply as it’s not a load bearing material

I cannot think of a superlative to express how wrong that is. The plywood is a crucial part of the timber frame structure. "Timber Frame" is a bit of misnomer as it conjours up images of an old tudor oak timber framed buildings. With modern timber frame, I call it "lightweight timber panel" as it is the combination of the very slender timber studs and the plywood that make the large panels strong enough to take the weight of the house. The timber studs on their own will twist and bend when put under load not to mention blow over in a strong wind just like the 3 little pigs. (I just read Bernard's post.....great minds think alike)

I still cannot work out where that bedroom is in context of the movement in the gable brickwork so I cannot tell if it is related, but if the builder who advised you it was OK to smash out the plywood panels is the same one who built the extension then heaven knows what other damage he has done.

You need a structural engineer urgently.

(Thanks Doggit)

 

[Doggit]

(I messed up the quote function so sorry if this is confusing, it refers to Marty's quote that builder said it was OK to remove plywood)

I've done that before, and learnt to cheat. Do the quote into another post, block and copy it, then edit the original post, and then paste it in.

Now as to the problem, I can see what you mean about the panels providing the structure, but where are the wall ties in this type of construction.

 

[wessex101]

Now as to the problem, I can see what you mean about the panels providing the structure, but where are the wall ties in this type of construction.

The wall ties are fixed to the plywood. https://www.lbsbmonline.co.uk/box-o...MIpuS02Nzy1wIV55PtCh2HKwwqEAQYAyABEgKGEPD_BwE

 

[stuart45]

They should be fixed through the sheathing into the studwork as well. Normally OSB is used nowadays.

 

[Doggit]

Now that's interesting. If it's supposed to be fixed to the ply, then they should have struggled to get it off, and there would have been wall ties on the back of the ply, or left on the wall; either scenario would have given warning signs.

 

[wessex101]

Now that's interesting. If it's supposed to be fixed to the ply, then they should have struggled to get it off, and there would have been wall ties on the back of the ply, or left on the wall; either scenario would have given warning signs.

If you enlarge the internal bedroom photos you can see a wall tie where the plywood has been smashed out. I'm guessing that wall is now an internal wall so it probably can be fixed but it will need a structural engineer to design the remedial work as those panels have been severely weakened.

 

[tony1851]

If it's modern timber-frame construction, the outer skin of brickwork will be tied to the panels; ripping them out leaves the brickwork unsupported.
The man who gave the advice was a cowboy, not a builder.

 

[stuart45]

Now that's interesting. If it's supposed to be fixed to the ply, then they should have struggled to get it off, and there would have been wall ties on the back of the ply, or left on the wall; either scenario would have given warning signs.

They shoudn't be in the ply sheathing alone, they are supposed to be nailed into the studwork.

 

[catlad]

Years ago I worked in a timber factory making timber framed houses and the outside skin of brickwork will be built up
using the ties from the timber panel, if you have been disturbing this then you will have caused this damage.