I’m installing a 1500 x 3000 lantern in a flat roof 3050 x 5500 the wall gap of 3050 has the supporting timbers taking the 1500 width lantern what size timbers or rsj’s would you use to support the lantern. Regards RR
Hi Jord The weight all in with glass is circa 400/500kg I’m taking the old roof off so we are raise the height to add some brick detail and adding a paraphit so can install larger size timbers. RR
I'd get some calcs done if I were you mate, or approach a joist manufacturer and get a price on engineered joists, can't risk guessing or putting your neck on the chopping block with that amount of weight.
Look engineeer timber like glulam beams, far stronger than the 9x2's or what ever size timber suggested, they will do the required calcs for you. Seen a few lantern openings done with glulam beams
Hi Jord I will give the lantern Company a call in the morning and see what the say on sizing plus a proper weight of the complete unit as it was a bit of a finger in the air for the weight of the glass. I will also find out how much a engineer will charge, that cost will probably half the total build cost. I will let you know the outcome. RR