Hi,
I am researching the possibility of converting my loft to become a 4th bedroom. We live in an Edwardian hipped-roof semi, and I've no intention of doing a hip-to-gable conversion, as I don't like the way it visually unbalances the pair of houses. Because of the hipped roof, I am limited as to where I can support new floor joists. My loft floor sits well above the wall plates, so I cant get access to rest steels or thicker joists on those, and because of the hip there is no gable to the outside wall to offer similar support.
One possible solution I thought of was to support the existing loft floor from below, to strengthen it up to meet building regs, since I think I can get beams to reach the wall plates from underneath if they are thick enough (9 inches or so). Also, it would give me maximum head height for the conversion. I currently have 4" x 2" floor joists spaced at approx 400mm. They are in good condition (no rot or woodworm) even though the house is over 100 years old.
Could I, for example, install a couple of large timber beams under the ceiling on the 1st floor, perpendicular to the loft joists (having stripped back the lath and plaster first of course, so the timbers meet). Or would I have to use RSJs? Does anyone have a rough idea on the thickness of timber or steels required? The span is approximately 3.5m and I'd be looking to install 2 beams in each of the 2 rooms under the loft. That's 2 in the main bedroom and 2 in the second bedroom. They'd be spaced about 1/3rd and 2/3rds distance across the rooms at around 1m intervals. Supported at the far ends by double skin walls, and supported in the centre by single skin spine walls.
I'd prefer to use timber here, as it's easier and lighter to handle, and would look more aesthetically pleasing in the rooms below than steels. However, I'm aware that the loft floor would need 30 minutes fire protection, so could I paint or varnish the timbers with a fireproof covering to meet regs? I think such products exist on the market.
I assume I will need a Structural Engineer for calcs, but would be grateful for an opinion from anyone who has knowledge on this subject, and if my idea is at least sound in principle.
Thanks, Jon.
I am researching the possibility of converting my loft to become a 4th bedroom. We live in an Edwardian hipped-roof semi, and I've no intention of doing a hip-to-gable conversion, as I don't like the way it visually unbalances the pair of houses. Because of the hipped roof, I am limited as to where I can support new floor joists. My loft floor sits well above the wall plates, so I cant get access to rest steels or thicker joists on those, and because of the hip there is no gable to the outside wall to offer similar support.
One possible solution I thought of was to support the existing loft floor from below, to strengthen it up to meet building regs, since I think I can get beams to reach the wall plates from underneath if they are thick enough (9 inches or so). Also, it would give me maximum head height for the conversion. I currently have 4" x 2" floor joists spaced at approx 400mm. They are in good condition (no rot or woodworm) even though the house is over 100 years old.
Could I, for example, install a couple of large timber beams under the ceiling on the 1st floor, perpendicular to the loft joists (having stripped back the lath and plaster first of course, so the timbers meet). Or would I have to use RSJs? Does anyone have a rough idea on the thickness of timber or steels required? The span is approximately 3.5m and I'd be looking to install 2 beams in each of the 2 rooms under the loft. That's 2 in the main bedroom and 2 in the second bedroom. They'd be spaced about 1/3rd and 2/3rds distance across the rooms at around 1m intervals. Supported at the far ends by double skin walls, and supported in the centre by single skin spine walls.
I'd prefer to use timber here, as it's easier and lighter to handle, and would look more aesthetically pleasing in the rooms below than steels. However, I'm aware that the loft floor would need 30 minutes fire protection, so could I paint or varnish the timbers with a fireproof covering to meet regs? I think such products exist on the market.
I assume I will need a Structural Engineer for calcs, but would be grateful for an opinion from anyone who has knowledge on this subject, and if my idea is at least sound in principle.
Thanks, Jon.
