Remove purlin props

[datadiyer]

Hi all,

I hope someone can help me. I'm hoping to convert my loft to a storage/playroom with pull down ladder. There are existing 3 x 2's I believe so they would need strengthening. There are also double purlins each side of roof. One thing i'd like to ask though. I've had someone to take a look to give me a quote, and they said that they can take out the props no problem, but the purlin would have to stay in place. They would however have to provide upright support to the lower purlin. Is this correct? They look quite sturdy purlins with quite sturdy props which surely must be needed to hold up the purlin. I currently have rosemary tiles which are being replaced with synthetic slate, so the roof load will be much lighter. Any thoughts?
Many thanks.

Untitled

• datadiyer
• 24 Aug 2009
• 1

Untitled

• datadiyer
• 24 Aug 2009
• 1

 

[datadiyer]

any ideas at all?

 

[Deluks]

Yeh, don't proceed unless this person provides calculations and drawings from a structural engineer.

 

[freddiemercurystwin]

Probably need a steel beam at floor level spanning between the walls beneath the existing purlins and timber props to support the purlins. Then the props can be removed. Your new timber floor joists can sit in the web of the steel beams to create your new floor. But to reiterate you need an engineer to get involved really and do not let a builder to just take the props out.

 

[datadiyer]

Many thanks,

Just as my instinct told me, structural engineer it is.

Thanks again.

 

[joe-90]

Probably need a steel beam at floor level spanning between the walls beneath the existing purlins and timber props to support the purlins. Then the props can be removed. Your new timber floor joists can sit in the web of the steel beams to create your new floor. But to reiterate you need an engineer to get involved really and do not let a builder to just take the props out.

This is VERY good advice.

 

[datadiyer]

Hi,
I agree on steel beams to support the lower purlin, but upright support timbers to support the top purlin would cut off half the loft space. Maybe bigger rafters from the lower purlin to the ridge beam? Would this be an option, as you can guess i'm no expert here.
Cheers.

 

[freddiemercurystwin]

There are probably several ways to safely remove the props, my suggestion is just one of them and is a very common solution provided the purlins are low enough down the roof. Without knowing the layout of all of the roof timbers and whats supporting what and what if any loadbearing walls there are beneath etc its very difficult to advise further. You either need to provide some more info/sketch/photos or all three on the forum or its time to speak to an engineer which frankly you should probably do so anyway. Whether its a playroom or habitable room and whether you are applying for building regs or not it should still be (structurally & fire regs speaking at least) converted in a method compliant with the regs.

 

[Deluks]

Hi,
I agree on steel beams to support the lower purlin, but upright support timbers to support the top purlin would cut off half the loft space. Maybe bigger rafters from the lower purlin to the ridge beam? Would this be an option, as you can guess i'm no expert here.
Cheers.

Adding some deeper timbers to existing might be an option. But you will probably have to add collar ties at the top (making a triangle at the apex to give a flat ceiling) These will reduce the span of the rafters somewhat meaning that it may be possible to lose the upper purlin entirely.

 

[datadiyer]

Hi,
Yes, I think that will be an option. I'm awaiting another builders advice but ultimately I think it will be a building regs job. Although i'd have to pay £450 to class it as a full loft conversion even though I only want it as storage without the props. Saying that, I may turn it into a habitable room further down the line.
Cheers.

 

[freddiemercurystwin]

My suggestion was to ensure its compliance with fire and structural regs for the sake of being sensible/safe rather than actually getting approval. Unless you get a builder witha brain like noseall or woody I think you need to be relying on an engineers advice not a builder at this stage. Of course there are some engineers with small brains too!