Converting round roof shed to straight pitch??

[Hooby Farmer]

Has anyone converted a double round roof shed into a straight pitch before. Our ‘big shed’ needs reroofed, well half of it does. One side needs new timber and tin and hasn’t been touched since the 60’s with a couple of leaks starting. The other side was re tinned about 20 years ago but now the timbers are rotten as well as the drain in the middle. Its 30ft to the centre, my head says it can be done. I just don’t know anyone with first hand experience who has done it/tried it.

 

[AJR75]

Looked at doing one similar a few years back As a steelwork contractor we declined the work as the columns were far too small to do the job required by retro fitting a set of portal rafters. Potential client was adamant it could be done however. Several months passed and a new frame appeared in place of the old one.

 

[mixed breed]

I had someone out to look at converting a curved roof to a mono pitch and although it's only 19ft wide I was told the stanchions weren't up to spec for the loading of a 9degree(iirc) mono pitch roof.

 

[Hooby Farmer]

I would be keeping the central columns that are there just extending them upwards 6-8ft or whatever the maths works out at, or maybe your including that.

 

[simmy_bull]

Has anyone converted a double round roof shed into a straight pitch before. Our ‘big shed’ needs reroofed, well half of it does. One side needs new timber and tin and hasn’t been touched since the 60’s with a couple of leaks starting. The other side was re tinned about 20 years ago but now the timbers are rotten as well as the drain in the middle. Its 30ft to the centre, my head says it can be done. I just don’t know anyone with first hand experience who has done it/tried it.

Some Dutch barns get converted with angle iron roof trusses I believe. There’s a shed where I work that the boss calls the Dutch barn but it’s straight pitch.

As has been said above the uprights always look amazingly small compared to what they spec for today’s sheds.

Can you post any photos?

 

[Hooby Farmer]

Yeah I’ll get a couple of pictures tomorrow.

 

[Hooby Farmer]

The shed is 49 feet wide, was way off thought it was wider . If I raise the rsjs up in the middle of the shed about 8/9 foot it would leave the rafters 25ish feet maybe a tad shorter would that be too far?

 

[multi power]

The shed is 49 feet wide, was way off thought it was wider . If I raise the rsjs up in the middle of the shed about 8/9 foot it would leave the rafters 25ish feet maybe a tad shorter would that be too far?

Of course that can be done, but a portal frame won't need support in the middle, but I don't think the existing uprights would be strong enough

 

[KennyO]

@Hooby Farmer price up a new portal frame before you start.
You are going to need new purlins and sheets anyway and labour which are a large part of the cost.

 

[simmy_bull]

The shed is 49 feet wide, was way off thought it was wider . If I raise the rsjs up in the middle of the shed about 8/9 foot it would leave the rafters 25ish feet maybe a tad shorter would that be too far?

The way I’ve seen it done was that each side had its own peak with a valley gutter in the middle which enabled the use of a lighter weight rafter.

I should think @KennyO might be on the mark with his comment if the only original part to remain is the legs.......

 

[Hooby Farmer]

I want to get rid of the valley if I could. What steel would you use something like 305*165 for a 50ft span. I can do the steel work myself and I've plenty of men it wouldn't be a huge job to throw up. But I would like to do it as cheap as possible

 

[Ritchie]

This information is worth how much you paid for it.
Possibly 254 x 146 x 31kg meter would be strong enough if the total span is 50 feet. You would need to extend the middle stanchion. At 15 degrees it wont be much more than 4 - 5 foot. Draw it out on a concrete floor with a chalk snap line, you'll get all your dimensions that way and it's much safer than off the top of a Ladder.

Ritchie

 

[multi power]

I want to get rid of the valley if I could. What steel would you use something like 305*165 for a 50ft span. I can do the steel work myself and I've plenty of men it wouldn't be a huge job to throw up. But I would like to do it as cheap as possible

What do you have avaagai the valley?

 

[Forever Fendt]

I had someone out to look at converting a curved roof to a mono pitch and although it's only 19ft wide I was told the stanchions weren't up to spec for the loading of a 9degree(iirc) mono pitch roof.

unless they were rotten at the bottom it would be fine with a tin roof using the original posts with a roof and side brace added it is a repair not a new build so spec and calcs not so much of an issue

 

[Matt]

why dont you replace the middle row of posts, (you would have to extend them anyway) and make it a propped apex roof. at least you would have a decent size steel in there.
we took a dutch barn down this year and replaced it. its surprising once the roof was loose how wobbly it became.
best decision we made. plenty of height and width for straw now.

 

[Hooby Farmer]

why dont you replace the middle row of posts, (you would have to extend them anyway) and make it a propped apex roof. at least you would have a decent size steel in there.
we took a dutch barn down this year and replaced it. its surprising once the roof was loose how wobbly it became.
best decision we made. plenty of height and width for straw now.

That's a big reason I'm consider putting the Apex roof on. I'm taking internal walls out as well as two concrete feed passgages, and opening up the whole space inside to make better use of the whole shed.