Steel I beam purlins, unusual in a house?

Chris Wilson

Chris Wilson

Chris Wilson

Permabanned
Joined
28 Nov 2003
Posts
10,695
Location
Shropshire
My bungalow has what I call purlins, (but may well have the wrong terminology), running the length of the roof space, one per side. They are steel I section beams about 12 inches deep by 6 inches wide.

The man who had it designed and built had a big farm machinery and steel buildings factory, which may explain it! Is this unusual? I can't sayI have ever seen it in any other bungalow!

I probably have some photos of it before I filled it with a load of stuff that "needed keeping" from the move here 20 odd years ago, but probably hasn't been touched since, you know how it goes.... ;)
 
Chris Wilson said:
My bungalow has what I call purlins, (but may well have the wrong terminology), running the length of the roof space, one per side. They are steel I section beams about 12 inches deep by 6 inches wide.

The man who had it designed and built had a big farm machinery and steel buildings factory, which may explain it! Is this unusual? I can't sayI have ever seen it in any other bungalow!

I probably have some photos of it before I filled it with a load of stuff that "needed keeping" from the move here 20 odd years ago, but probably hasn't been touched since, you know how it goes.... ;)
Click to expand...

My grandparents old bunglow had the same. Might have been a design thing at some point in the past.
Theirs was also a bit more industrial/commercial as well. Ceiling internal suspended tiles as opposed to plasterboard ceilings
 
Last edited:
FWIW I was told in my 1880's cottage that we needed an RSJ in the loft to support a chimney breast that was removed. It was using gallows brackets which at the time of installation were "self certify" (a scheme that didn't work).
 
relations 20yr old bungalow doesn't - does steel give a longer/lighter span, but cost more ?

new build roofs, seem to be impractically built with thinner multi section wood trusses that might be stronger/cheaper, but give little potential for loft boarding or loft conversion.
 
dLockers said:
FWIW I was told in my 1880's cottage that we needed an RSJ in the loft to support a chimney breast that was removed. It was using gallows brackets which at the time of installation were "self certify" (a scheme that didn't work).
Click to expand...

These were part of the original plans, which I have, so I know they were not added subsequent to the original build. I guess he had access to cheap steel and liked it as a construction material :) Thanks.
 
jpaul said:
relations 20yr old bungalow doesn't - does steel give a longer/lighter span, but cost more ?

new build roofs, seem to be impractically built with thinner multi section wood trusses that might be stronger/cheaper, but give little potential for loft boarding or loft conversion.
Click to expand...

There's nothing light about these things. I guess I could measure the section and the length and look up their weight, but they must be well over a ton per span.
 
There's a few houses where i live built around the 1970s which have steel in the roof but are classed as 'non standard' construction. This effectively means its more difficult to get a mortgage on them but i assume that was maybe not the case for your current house?

I would have thought your assumption in the OP is correct in that the guy used what he knows for using steel instead of timber purlins but I guess it may have given him more freedom to not have as many if any loadbearing walls below as the roof would be carried by the external walls and full spanning beams. Without seeing the plans / layout of your house I'm working on a best guess. There are many reasons for using steel over timber as above or the size of the steel would be minimal compared to the depth of a timber purlin to span the same distance etc. As a rule of thumb though a trussed roof soley of timber would be the norm.
 
It is common, I did roof inspections on two blocks of flats in Kent a couple of weeks ago and they had steel purlins and a steel ridge beam in all of them - built probably around the 50’s when they still built properties with fireplaces.
 
Last edited:
I think it was built mid seventies, would need to check, time flies. There was no issue getting a mortgage, I don't recall any comment at all on the steelwork.

My main beef is he used that aerated concrete block for the inner walls. The stuff you can cut with a bread knife and is hell to secure stuff too. Warm as toast in winter, but I would prefer the "normal" concrete blocks as the inner walls.

I haven't seen houses double skinned in standard size bricks for years, do any builders still do that?

Thanks for the replies!
 
Bungalows do tend to have larger floor area and spans than a typical two storey house. A timber purlin would have similar dimensions to your steel beams. Maybe it was a question of supply at the time it was built, large section timber is not always economic. I do like a purlin roof. Trussed rafters lose all that space above the ceiling.
 
Last edited:
Chris Wilson said:
My bungalow has what I call purlins, (but may well have the wrong terminology), running the length of the roof space, one per side. They are steel I section beams about 12 inches deep by 6 inches wide.

The man who had it designed and built had a big farm machinery and steel buildings factory, which may explain it! Is this unusual? I can't sayI have ever seen it in any other bungalow!

I probably have some photos of it before I filled it with a load of stuff that "needed keeping" from the move here 20 odd years ago, but probably hasn't been touched since, you know how it goes.... ;)
Click to expand...

My guess is that he had it in mind to convert the loft at some stage. Check the floor in the loft! If that is over-engineered as well then you have the cheapest upward extension ever!
 
Last edited:
You must log in or register to reply here.
Back
Top Bottom