Hi there, I am about to build a garage which will a roof span of 6 meters. Im intending to bolt 6x2 at 4 inch alternative gaps over 900mm overlap using 10mm nuts and bolts with 50mm square washers. There will be a 300mm overhang front and back and spaced at 600mm centres. The roof will slope from 3.2 mtrs to 2.4mtrs which will be sheeted with 11mm osb and the metal sheeting. The brother in law who know everything!!! seems to think this will need support legs in the garage to prevent bowing. I'm thinking it will be fine. What are you thought on this people??
Normally most timber merchants won't stock 6.6m lengths of timber. Typically they will be a special order, so you will have to have overlapping joints. The are going to me mighty heavy to lift and position. I would be tempted to make up my own I beams / box beams with cheaper timber and OSB/Ply.
What about engineered I joists much easier to work with, span not an issue, lighter to handle. https://www.jamesjones.co.uk/ewp/
That what I was saying about the I beam, easy enough to knock up on site and a lot cheaper than the commercial ones. Last time I made some I used the calcs I found the web somewhere
I'm reading it to be a pitched roof as opposed to an apex. I'm also thinking that it hasn't got enough fall on it to not become very heavy if it got covered in snow.!!! Any road 6x2 are not strong enough for that span even at 400 centres. If at all possible I would fit a steel across it in the middle, it shouldn't interfere with head height as it would be around 2.8 metres less its depth of say 150mm so 2.65 metres.
Just read it again. Its a pent roof????? Don't bolt it. Thats a cowboy job Run a purlin/beam half way or get some 12x2 at 7m and thats pricey stuff