roofing farm shed

mick 101

Hi there. I have a question for any roofers/builders out there. I am building a farm shed, a freestanding "lean to" type. 15m wide, 7m back to front, approx. I plan to concrete eight esb poles in the ground and bolt four 6x3s to each pair of poles front to back. This will give me three 5m bays. Then on top of the 6x3s, running from side to side, I need to fix some maybe 4x3s at 1m spacings to take the felt and the corrugated sheets. Basically I need to know will these timber sizes be strong enough to take the roof weight and not sag. Thanks, Mick.

steloide

Hi Mick.
That seem like plenty to me for extra turn the 4x3s on there edge and close the 1m gap to about 800cm that should be loads.

paddy147

mick 101 wrote: »

Hi there. I have a question for any roofers/builders out there. I am building a farm shed, a freestanding "lean to" type. 15m wide, 7m back to front, approx. I plan to concrete eight esb poles in the ground and bolt four 6x3s to each pair of poles front to back. This will give me three 5m bays. Then on top of the 6x3s, running from side to side, I need to fix some maybe 4x3s at 1m spacings to take the felt and the corrugated sheets. Basically I need to know will these timber sizes be strong enough to take the roof weight and not sag. Thanks, Mick.

7 x 2s at 400mm distance did perfectly for my large garage.:)

Lean too roof that has a depth span (highest to lowest roof point) of 7 meters


Non drip tile effect cladding on it and also a Daltex breathable felt underneath..just for added protection.Garge is alarmed aswell...so maybe no harm for you to install an alarm in it...if needed


So 6 x 3s should be grand.

martin46585

If I am reading this right, your rafters will be made of 7mt 6x3, and your purlins will be 5mt 4x3, placed on top, both of the timbers will sag greatly in the centre of each bay, and with the added weight of sheeting and a covering of snow will put considerable load on a very unstable structure.
Wind bracing will be essential in a free standing building, and in a timber build would be much harder to achieve suitable rigidity.
Why not use steel ip sections, much more suited to these type of structure, and will stand the test of time long after the timber has.....

mick 101

What do you mean by steel ip sections Martin. Would these be a stock item or made to order. Im on a tight budget here but I gather what you are saying about the sag on the 7m rafters alright. I dont want to have another support in the centre taking up floor space. Where might I get these steel sections?

mick 101

Maybe something like these? http://www.donedeal.ie/for-sale/farmsheds/4456621

cgarrad

7m 6x3 with snow will snap.

Can you put in a center pole?

an acro prop with some extra 6x3 will work fine.

mick 101

No centre pole. what about a 8x3 steel purlin for the 7m span??

martin46585

mick 101 wrote: »

What do you mean by steel ip sections Martin. Would these be a stock item or made to order. Im on a tight budget here but I gather what you are saying about the sag on the 7m rafters alright. I dont want to have another support in the centre taking up floor space. Where might I get these steel sections?

Have a look through this document http://www.agriculture.gov.ie/media/migration/farmingschemesandpayments/farmbuildings/farmbuildingspecifications/pdfversions/S101.pdf

Which will give some valuable information on these type of structures.
At first glancethe steel frame may seem expensive, though will me much less labour intensive than timber, with much less timber involved, so may not be so much more..

mick 101

martin46585 wrote: »

Have a look through this document http://www.agriculture.gov.ie/media/migration/farmingschemesandpayments/farmbuildings/farmbuildingspecifications/pdfversions/S101.pdf

Which will give some valuable information on these type of structures.
At first glancethe steel frame may seem expensive, though will me much less labour intensive than timber, with much less timber involved, so may not be so much more..

Great document. Thanks.