Loft Conversion, a bit strange? Support for Purlin? Pictures

[Spanky123]

Hello all,

Part way through a "Loft Conversion", we have a "normal" early 20th century mid-terraced property, the unusual thing about it is it has another 2 rooms tacked on one side over a "driveway" which is in turn connected to the next house in the terrace.

So, I have a mid terrace and a half (like two terraced houses with no ground floor in 1 half.

We have laid new joists and floors in both halves of the loft, they are separated by a wall that contains 2 chimneys.

To gain access to the 2nd loft we have removed 1 chimney and replaced it with a doorway.

The wall in question also supports 1 end of 2 purlins, 1 about 3m in length and 1 about 4m in length. (One comes from either side of the property, i.e. next door each side.

The question is....

When the chimney has been removed and the opening is made, is the concrete lintel above the door way ok to support the ends of the purlins where they used to sit on the wall.?

I have enough of the Chimney wall as you can see to place the lintel with direct support from that wall on both sides. The purlin ends will sit near to the centre of the concrete RSK.

Perhaps a bit late now, but thought I'd check.

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• Spanky123
• 4 Nov 2008
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• Spanky123
• 4 Nov 2008
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• Spanky123
• 4 Nov 2008
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• Spanky123
• 4 Nov 2008
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• Spanky123
• 4 Nov 2008
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[noseall]

i would say no. but i'm no structural engineer.

also, the brickwork to the left looks shambolic and would need re building.

and, the neater brickwork to the right looks as if it corbels in toward the bottom three courses. or is this just soot?

 

[JohnD]

Are you in touch with the Building Control Officer?

 

[Spanky123]

"the brickwork to the left looks shambolic and would need re building"

The brickwork to both sides has been re-built, the shables on the left is all too be removed, however we have so far only removed enough material to fit the first lintel, which is built on fresh brickwork both sides, the shambles is what is left of the brickwork from the back wall of the chimney, it will be rebuilt when the 2nd concrete lintel is fitted, making the full doorway.

"the neater brickwork to the right looks as if it corbels in toward the bottom three courses. or is this just soot?"

This is just soot.

"Are you in touch with the Building Control Officer?"

No.

 

[JohnD]

"Are you in touch with the Building Control Officer?"

No.

Ah.

 

[Spanky123]

I forgot too mention, the roof has 2 purlins the size of the one in the photo in each loft, there is another lower down, just out of the shot, this is obviously untouched.

I am wondering wether to use a steel joist rather than an Concrete Lintel, It would still be realatively easy to swap it in.

I would rather be over cautious if you see what I mean.

The rooms are only for storage so I had no real intention of involving the BCO.

The builder completing the work comes highly recommended and has worked on lots of the nicer homes nearby, and local businesses, he has also worked for me in the past with no problems.

 

[PJ1]

For your education Spanky, the Building Regulations make no distinction between habitable rooms and storage rooms. It's a loft conversion and the regulations DO apply. If you get copped you could be in for a fine (upto £5K per offence comitted). You are also likely to come seriously up against it if/when you sell or indeed want to remortgage the property. Ask yourself where the builder will be then - it's not hard to imagine......
Recommend you see the Council BCO asap.

I would suggest that if your builder is so good he would simply calculate the load reaction coming onto the lintels from the purlins and compare that to the allowable safe load (as stated by every pre-cast lintel manufacturer for their particular product - Available from the mechant but not B & Q!)......

 

[Softus]

To gain access to the 2nd loft we have removed 1 chimney and replaced it with a doorway.

IMO, this is notifiable.

When the chimney has been removed and the opening is made, is the concrete lintel above the door way ok to support the ends of the purlins where they used to sit on the wall.?

Is this some kind of joke?

You're posing a question about structural loading on an Internet forum, with no dimensional or loading information, and asking for an answer based on a few frankly grotty pictures taking at different times and stages of work, that show very little except an abysmally small and weak bearing surface for each end of a new lintel?

FFS engage a structural engineer before it's too late.

I have enough of the Chimney wall as you can see to place the lintel with direct support from that wall on both sides. The purlin ends will sit near to the centre of the concrete RSK.

I have no confidence that you're using the same meaning of the word "enough" as I would be in the circumstances.

Perhaps a bit late now, but thought I'd check.

Very late.

I am wondering wether to use a steel joist rather than an Concrete Lintel, It would still be realatively easy to swap it in.

You're wondering? You're wondering?

Why isn't your builder wondering, AND deciding, AND providing you with written calculations?

Sack your builder, withhold whatever you owe him, and notify the BCO now.

 

[Softus]

BTW, this topic should be in the Building forum, not this one.

 

[jeds]

It's impossible to tell what loads are on the purlins but just intuitively those concrete lintels look totally inadequate to me.

I went to do a survey on a brand spanking new flat about 18months ago to find, when I arrived, that the stairwell and part of the roof at the top of the building had collapsed over night due to a failed concrete lintel.

 

[Stingray6893]

As I think Softus mentioned earlier, it is nigh on impossible to calculate whether that lintel will hold. A) Is it a PC lintel or a PT lintel. PT are significantly stronger. B) We have no dimensions etc, roof pitch, cladding material etc. etc. All are VITAL to calculate anything, with out this we would be merely speculating.

But speculate I will, initially I am going to ask if the purlin actually spans onto the top of the lintel, and if so is it sitting directly in the middle of it, as even if the lintel can take the load generally, applying a pointload to a support is cause for a whole lot more of maths, and hard maths. Firstly, I would spin the lintel 90 degrees and lay it on it's side, then lay the other one next to it in the same fashion, this will instantly increase the combined capacity. Then I would also look at deepening your padstone, and generally just making it larger, too small for me.

Yeah and the BCO isn't a bad shout. The majority of work I do here is relaying messages to them about what I'm diong (structural engineer to clarify) but yeah. Pay someone to do this for you, it may cost you now but save you oodles in the long run.

So NO, I would not trust it.

 

[joe-90]

The original post is from Nov 2008 - I bet the house has fallen down by now eh?

 

[Static]

Simple plank PC lintels are rarely suitable for point load bearing.. so to answer your question.. no its not.. put something more suitable in..

As said a few times above get some professional advice on size.. as well as looking over the rest of the conversion for other "minor" errors in build..

 

[catlad]

I think it will have been sorted on way or another stingray as it is a 4yr old post.

 

[Nige F]

The original post is from Nov 2008 - I bet the house has fallen down by now eh?

Stingray meets Joe 90 - all we need now is Thunderbirds - F.A.B . FFS