cracked purlin structural failure

[Koenigswelle]

if i recall correctly the purlins are about 9 x 3

 

[Koenigswelle]

I do not think I have seen a slate roof with purlins that size in that shape for a long time.

do you mean they are undersized or oversized and by shape you mean bowed ?

 

[Koenigswelle]

is this forum politically correct, i do not recall writing ****ing

edit yes it is

 

[Koenigswelle]

n terms of time for scaffold, surely if you are getting a price for the job it does not matter?

well yes and no, my tenants are in my opinion being somewhat obstructive because they are home office covid victims and cannot accept noise !
I am still looking into the legal aspects of this but i believe i will prevail because it is a health and safety issue if the roof slides off into the street or collapses in on them in their beds, consequently for them 1 week is preferential to 4 weeks

 

[frutbunn]

Just to confirm the structural work is not covered by a competent person scheme.
The competent persons scheme in this instance would only cover Part L (thermal insulation), although in this case your LA may take the view Part L does not apply, there is some scope for different interpretations with regard to replacement roof covering/structure when the insulation is not incorporated in this part of the structure.

 

[Koenigswelle]

Just to confirm the structural work is not covered by a competent person scheme.

only insulation ? you mean like a warm roof, surely they are covered to at least replace battens felt slates leadwork etc ?
Could you please direct me to the relevant regs or documentation about them where all parts not just Part L are explained.

 

[frutbunn]

only insulation ? you mean like a warm roof, surely they are covered to at least replace battens felt slates leadwork etc ?

The structural work requires B regs, however the competent person scheme does not cover structural work so you will need to appoint B control for this.

 

[datarebal]

do you mean they are undersized or oversized and by shape you mean bowed ?

No I mean a slate roof with decent purlins in a caved in shape. The purlins would have been fine if the struts were still there..
Assuming it's just carpentry then it's a straightforward job.
A good chippy would do it blindfolded
Working in conjunction with the roofer keeping this weather tight easy
If the walls have actually moved then it's a bit more involved.

 

[catlad]

Very unusual to see that type of roof in that condition.

 

[tel765]

If there are two purlins per side then there's only evidence for one per side in the pics so far - why would two purlins per side be used across that brief span? Perhaps because of the low pitch?
Is the ridge firmly supported at each end?
Pic's showing two per side would help.
The structural reason for two purlins per side could have been for extra support after all the supporting framing had been removed.
Notice where the purlins are set into the party wall that the pockets have been worked on since 1900.

Is the loft chimney breast lower down the party wall?

 

[Koenigswelle]

The purlins would have been fine if the struts were still there

Only one of the 4 purlins is showing signs of bowing (now cracked). In the roof space originally there were no struts only thin timbers which hung the original thin ceiling joists to the rafters.
You are referring to the components called collar/strut in my attached cutroof pic. As I mentioned earlier a survey had indicated that there appeared to have been some settlement but it was not thought serious enough to impact a mortgage, whether they actually looked in the loft seems doubtful.

 

[Koenigswelle]

there's only evidence for one per side in the pics so far

unfortunately i did not take more pics of the roof assembly, but trust me there are 2 purlins per pitch, i cannot readily get more pics as i am in Germany and the house is not !
The purlins look to be all original equipment ie not assembled later, all same dimensions rough cut and the same degree of "patina".
By "all supporting framework removed" do you mean the so called collar and struts referred to earlier by another poster ? I cannot imagine why a previous owner would do that because when I took it over the loft
was not a usable space there does not appear to be a logical reason for its removal, assuming it was there. Not sure if it is relevant but this house appears to have been at one time an end of terrace although now it is mid terrace, the house adjoining what might have been the end is a completely different internal structure, it is 2 bedroom not three, bathroom is in a different place and no two storey outrigger. Would an and terrace need more support in the roof ? in pic green paint is mine to the right is a different construction

 

[Koenigswelle]

pockets have been worked on since 1900.

on the left (rear) pitch i took out the complete chimney to floor level. There is a concrete lintel supporting the new brick that was inserted to bring the inner skin up to roof level and the roof was patched over.
This is not the side which has split. I am not entirely sure but I think that we had some mortar left over and as the mortar around the two visible pockets was decayed it was raked out and the excess mortar used to patch it up.

 

[Koenigswelle]

Is the loft chimney breast lower down the party wall?

Both chimney breasts are entirely in my building, rear is now removed front untouched. There is a picture on pg.1 which shows my front stack, that is under my neighbours entrance hall his chimney is on the other side

 

[Koenigswelle]

The structural work requires B regs

I guess i need to discuss this in more detail with person who does the roof, perhaps also ask the council