removing outbuilding/workshop roof

[seanc]

I have a outbuilding/workshop that currently has a very saggy corrugated fibre cement (possibly asbestos but i can get it disposed of locally if thats the case) roof.
Whoever build it decided to fit 1 joist along the 4m span rather that the several front to back on the shorter 2m span the joist has bowed and its letting in water between the sheets.
I am looking at removing the roof and replacing. Its a very low pitch so tiling isnt really and option, I have seen various other lightweight corrugated sheet options but the dont look the best.

I will probably put some joist hangers and new joists in and get rid of the bowed one but can anyone think of any other options for coverings ?

 

[Mark 5]

I have a outbuilding/workshop that currently has a very saggy corrugated fibre cement (possibly asbestos but i can get it disposed of locally if thats the case) roof.
Whoever build it decided to fit 1 joist along the 4m span rather that the several front to back on the shorter 2m span the joist has bowed and its letting in water between the sheets.
I am looking at removing the roof and replacing. Its a very low pitch so tiling isnt really and option, I have seen various other lightweight corrugated sheet options but the dont look the best.

I will probably put some joist hangers and new joists in and get rid of the bowed one but can anyone think of any other options for coverings ?

As you are going to install new joists, a GRP roof.

Some quality sub- decking as you don't want to have to do the job over, lay GRP. light weight and done right will last years.

Take a gander at a product called Filon GRP roof sheets.

When removing old roof, if asbestos, apart from obvious precautions, do so on a windless damp/rainy day if possible.

 

[addjunkie]

Insulated box profile. Various styles available.

 

[Agroshield]

Insulated box profile.

We should ask in which direction the roof falls (or in which direction the sheets need to span).

If he happens to need 4m long sheets, there may be a cost implication due to transport. They will be a lot quicker to lay but might need two people.

 

[gaz1]

can you post a couple of pics up please

as goes for the roof i know of a few ways but it depends on what you want to pay out as replacing a roof isnt cheap

as goes for the metal roof depends on how visual looking you want most go for box profile however there is a tile looking metal roof sheet

our roofs are low stone broken back roof to concrete single fall roof all depends on your degree of roof



or tile effect roofing sheet

 

[finyuk2005]

that tile effect stuff looks really good!

 

[gaz1]

on the shed i went a metal box profile roof

 

[seanc]

Sorry the pitch runs the short span and the sheets currently run the shorter span so only 2m sheets would be required.
Its only a single skin block structure so I’m also thinking of cladding it and possibly insulating and putting a more secure door/window in as currently just wooden single glazed units

 

[Agroshield]

It's only a single skin block structure so I’m also thinking of cladding it and possibly insulating...

If you have to re-roof it anyway, and if it is possible, consider insulating it on the outside (maybe insulated render) and making the sheets overhang more. That way you maximise the interior space for all your junk. It makes the inside more fireproof and also gives a solid surface to which you can screw things.

 

[roofman]

18mm plywood and a performance felt

 

[brightspark]

18mm plywood and a performance felt

View attachment 468345

nice job

 

[roofman]

nice job

Thanks A

 

[gaz1]

Sorry the pitch runs the short span and the sheets currently run the shorter span so only 2m sheets would be required.
Its only a single skin block structure so I’m also thinking of cladding it and possibly insulating and putting a more secure door/window in as currently just wooden single glazed units

so is this but has an apex roof

 

[gaz1]

Whoever build it decided to fit 1 joist along the 4m span rather that the several front to back on the shorter 2m span the joist has bowed and its letting in water between the sheets.
I am looking at removing the roof and replacing. Its a very low pitch so tiling isnt really and option, I have seen various other lightweight corrugated sheet options but the dont look the best.

Sorry the pitch runs the short span and the sheets currently run the shorter span so only 2m sheets would be required.
Its only a single skin block structure so I’m also thinking of cladding it and possibly insulating and putting a more secure door/window in as currently just wooden single glazed units

you will still need wall plates and rafters as well as cross members to go on the roof

but you can cheat a little if you fit 3-4 rafters and then run your beams internal to those rafters you will be able to fasten the boards or metal roof down solid

 

[sickpup]

Been working on the Father in Laws garage when I've had the time over the last few months, it's not much different to yours with one angle iron joist across a 4 metre span.

I've insulated with poly sheet and 2" Polystyrene sheet, 11mm OSB over the top which has stopped most of the moisture coming through the 60 year old concrete block walls and massively reduced the damp in there.
Another Son in Law fitted a box profile metal roof but as they are up a valley in South Wales next to a river the condensation is horrendous. Next year I'll be fitting proper joists and fitting an insulated box profile metal roof and then likely add further insulation between the joists.

 

[500e]

Quite a few Low profile Tesco buildings use that pressed tin tile effect roof usually has 80 to 100mm bonded insulation on it

 

[RonMig]

I rebuilt my workshop(shed) a few years ago, going from almost flat roof of corrugated plastic (dripped a lot) to corrugated tin over 18mm OSB...
Made my own trusses etc, probably too many but I wanted it to be strong...


Very happy with the result, completely weather proof

 

[seanc]

I would like to put a pitched roof on but unfortunately out outbuilding nearly touch's next doors, maybe a 10cm gap between so its not really an option

 

[seanc]

Sorry i meant dual pitched, There would be no way of getting guttering on the back side though

 

[gaz1]

a single pitched roof can be made higher as long as the top of the roof does not go past 2.5m high

ive shown you how to fasten down the roof using wall plates and rafters on a single wall build

doing it that way means you can fasten your roof down in 4 places and also insulate between the rafters

dont forget to felt the roof as well