Suitable lintel for an outdoor project

_Sam_

Hello everyone, I'm building a gazebo-like structure in the garden, dimensions are 5m length and 1.5m depth. I'd like the roof sloping from front to back, and this is my question - is there a lintel that would be suitable for an outdoor project like this, that would span the entire 5m length?

This would only be needed at the front - at the back there are 4 posts concreted in across the 5m length, and will have timber on top to support the roof. But at the front I'd like an uninterrupted view so was hoping to have just two posts one in each corner of the gazebo, and have a lintel of sorts to span the 5m length to support the front edge of the roof. The posts are 100x100mm, and the roofing sheets are lightweight metal.

stuart45

Use a timber lintel. It's not carrying a lot of weight. If you ever need a timber lintel with extra strength, you can make up a Fitch beam, which is a compound of steel and timber. In your case timber alone should be fine.

ThisIsWeird

What size, Stuart? 8x2 inch?

stuart45

ThisIsWeird said:

What size, Stuart? 8x2 inch?

Yes, 8x2 would easily span 5000mm.

_Sam_

Brilliant thank you both so much! 

Section62

_Sam_ said:

Hello everyone, I'm building a gazebo-like structure in the garden, dimensions are 5m length and 1.5m depth. I'd like the roof sloping from front to back, and this is my question - is there a lintel that would be suitable for an outdoor project like this, that would span the entire 5m length?

This would only be needed at the front - at the back there are 4 posts concreted in across the 5m length, and will have timber on top to support the roof. But at the front I'd like an uninterrupted view so was hoping to have just two posts one in each corner of the gazebo, and have a lintel of sorts to span the 5m length to support the front edge of the roof. The posts are 100x100mm, and the roofing sheets are lightweight metal.

Your main problem will be with the roof being lightweight and monopitch - it may be vulnerable to lift forces in the wind.

Make sure the roofing sheets are securely fixed to the timber, expecially round the edges, and that all the timber structure is securely fixed to the timber below it, so the roof is effectively anchored into the ground.  Consider using restraint straps to make sure the roof is securely attached to the support posts.

Eldi_Dos

Would it be possible to have the two front posts taller and use stays to support the 5m span.

Kiran

4.8m will be the longest standard length you'll be able to buy. You need a decent timber merchant for oversize lengths. You've already had the comment about uplift, make sure you have something between the front and back to stop the longer span twisting. 5m unrestrained, even on an 8x2 will have a decent amount of deflection at the mid span. If you have joists running at 90 degrees (between the front and back bean) you will be able to get enough restraint. If you google TRADA tables and look at the joist sections you'll be able to see a minimum size joist for the span depending on the spacing and the load from above. Not sure where you are based, but if allow for snow load it will stop your sheet from sagging in the event you have a bad winter

casper_gutman

You don't need a decent timber merchants as such - even Selco will sell you a 6 metre long 9x2 or 9x3 - but certainly it's a a step up from what you'll find in a typical DIY shed.

FreeBear

Have a cycle shed at work that has fibreglass roofing sheets (probably around an unsupported 2m span). Last time we had some real bad winds, the whole lot got trashed. An extra support across the middle would probably saved them from being damaged.