Loft conversion/Cut Purlin

RMIM · 7 Aug 2008

^woody^ said:
It would help if you explained exactly what the builder has been commissioned to do and if this is a proper conversion going through the required approvals, or if your mate has just asked for a bargain basement job and is getting what he has asked for.

It's easy to nit-pick pictures, but I'd like to know the background.

The builder was told to convert the loft into a spare room that could be used occasionally.

The builder should have advised my mate that he needs approval etc. Im not sure if every kind of loft conversion needs approval, but as the builder has cut purlins etc it should have been obvious to him and he should have said something.

I have posted the pics up just to see if the builder is doing things right, or if things will start sagging one day.

I think the builder might have convinced him that he did not need approval.

LOAM · 7 Aug 2008

every conversion that involves modification to structure requires Building Regs, if it doesn't involve Part B you can do it under notice but its unlikely tbh.

They will want to look at proposed insulation methods to this roof as well.

Someone has already said this but halt work now and get it sorted as it will turn up on searches if he ever decides to sell it, he's throwing his money down the drain if he cant sell is as a habitable room which he wont be able to without a completion certificate

If he is in a conservation area he will also have needed planning for that roof light.

The new joists, they aren't bearing on the old ceiling joists are they ? cant tell from picture

Deluks · 7 Aug 2008

LOAM said:
he cant sell is as a habitable room

He won't be able to sell it as a safe and usable roof either!

^woody^ · 7 Aug 2008

LOAM said:
every conversion that involves modification to structure requires Building Regs, if it doesn't involve Part B you can do it under notice but its unlikely tbh.

You can do any work under a building notice - even if it does involve part B.

We've done lots of loft conversions under a notice. Often its when someone can't get the drawings done in time

^woody^ · 7 Aug 2008

RMIM said:
I think the builder might have convinced him that he did not need approval.

Thats fine, but it's quite common for the customer to want a cheaper job and instruct the builder to do the work outside of any required regulations.

That does no absolve the builder in this case, but its good to know exactly what terms the builder was engaged on.

Its one thing to do a conversion properly and not apply for the required permissions, but another to do it incorrectly and not apply.

Your mate really needs to clarify what the builder has in mind to ensure that the conversion is structurally sound. Then he has to decide if he is happy to continue in this context, or whether he wants to get building control involved

LOAM · 7 Aug 2008

^woody^ said:
LOAM said:

every conversion that involves modification to structure requires Building Regs, if it doesn't involve Part B you can do it under notice but its unlikely tbh.

Click to expand...

You can do any work under a building notice - even if it does involve part B.

We've done lots of loft conversions under a notice. Often its when someone can't get the drawings done in time

in the case of a loft conversion that's probably ok (not sure its an age since worked on such a small project). However any thing which needs a Fire Certificate or is a to be used as a work place (Part II of the Fire Precautions (Workplace) Regulations 1997) or involves the erection of any building fronting onto a private street will need to be full plans submission

Norcon · 7 Aug 2008

Shytalkz said:
Norcon said:

And removing it will have no detrimental effects on the overall soundness of the structure.

Click to expand...

Complete bollix.

It would be better if you could explain why you think this.

Have you been on site and measured the rafter dimensions ?.

I will just reiterate that the rafters are most likely 5" x 3" s and adding what looks like 5" x 3" purlins to a roof like this will add little strength to the structure. In fact they are probably adding unnecessary weight to the structure.
Just look at the span for starters. All they are doing is aligning the rafters.
The purlin in that pic will have little or no load bearing capacity.

Shytalkz · 7 Aug 2008

Norcon said:
It would be better if you could explain why you think this.

Because it is.

Norcon · 7 Aug 2008

Shytalkz said:
Norcon said:

It would be better if you could explain why you think this.

Click to expand...

Because it is.

Thats not an answer !.
Do you know the dimensions of the rafters ?.
Also I think you have stated you are a structural engineer.
In this case you should know the load bearing capacity of a 5" x 3" purlin.
Over a long span it amounts to very little and if the rafters are undersized then you have a sagging roof.

You can also see the span in one of the images.

Also Gangman has already stated he would remove the purlins.
If the structure would be left unsound after removel then why have you not stated so ?.

Shytalkz · 7 Aug 2008

Undersized by what criterion? Modern design standards? Yes, but it's an old roof, ergo, modern design standards are of no relevance for the original loading/arrangement. Alter it and it does have to comply with current standards - as does every other structural element. The FoS in current standards are quite large, hence the bigger section sizes. That does not mean that the purlin is - or was before the numpty chopped it - redundant.

The purlin is doing some work in reducing the span of the rafters; it's removal - or chopping in this case - will require those rafters to span further than they did, with the same or greater load. Thus, they will deflect and the lack of tying at the eaves is likely to result in spread there. Again, look at the photos and you will see the plate does not line through with the inner face of the masonry. This could of course be how it was built, but there is insufficient information one way or the other.

If the structure would be left unsound after removel then why have you not stated so ?.

Try reading my first post in the thread.

jbonding · 8 Aug 2008

Its obvious from the pics that this is a bodge, it is possible the customer could of brought it on themselves, ie we will use it ocasionaly or for storage and we dont need to involve bco. Out of interest what are they paying for the conversion, I just lost out on a loft conversion and i think the main reason was i wouldnt start without the partywall notice being given to the neighbour. Ive drove past and it looks like they are doing a decent job from the outside but who knows whats goin on inside, you pay for what you get and looking at the pics of this one id say they are paying for what they get

^woody^ · 8 Aug 2008

Shytalkz said:
Because it is.

£95 please. Ker-ching!

LOL

Shytalkz · 8 Aug 2008

Plus VAT

RMIM · 8 Aug 2008

Rafters 2"X4"
Purlins 2.5"X3.5"

Deluks · 8 Aug 2008

Do you know if there were any struts (diagonals coming from the purlin to the floor) before this roof was hacked about?

diynot

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Loft conversion/Cut Purlin

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