Search the Community

HI all, I have used this forum for years but finally have to pose my own question rather than simply leech off others… I am replacing the existing felt flat roof on my 1970s kitchen extension with a warm roof build up of (existing) 18mm ply deck / Alutrix vapour barrier / 150mm PIR / 18mm ply / EPDM. I would like to add a flat roof light while I am at it which brings me to my question(s)… The roof dimensions (exterior) are 3.8m x 4.2m and the joists are 150 x 50mm at 40cm centres spanning 3m. I have currently narrowed down to two options which are as follows: 1. Install a 1m x 2m rooflight which would mean cutting 4 joists - I was planning to treble the joists at both ends and double the headers on the long sides (sistering joists and using hangers/fixings etc as outlined in building regs). 2. Install 2 x 1m x 1m roof lights which would mean cutting two joists for each - in this case I would only double the joists at either end but still double the headers. This design would leave two whole joists between the two roof lights. Option 1 is both cheaper and easier in that the EPDM could be a challenge with two roof lights to work around and clearly one window is cheaper than two! However, i feel that option 2 is better structurally but I would really appreciate some input as to the proposed design for option 1. One corner will also sit above a window lintel which is unavoidable in either lay out! Any advice would be greatly appreciated! Many thanks in advance, Will

Hey, would really appreciate your views on this one! Looking for thoughts on structural support for block and beam on a new build with basement and the various preferences from my designers Basement: 300mm concrete walls, internal cavity with insulation, inner leaf block, plasterboard Ground floor upwards: outer leaf brickwork, cavity with insulation, inner leaf blockwork My Architect wants an unbroken insulation zone from the basement to the roof, and to make this happen the block and beam to ground floor will sit on the inner leaf blockwork built up from the basement 300mm slab. We will also have block and beam on the 1st floor, so again the block and beam will sit to the inner leaf blockwork. Architect's request: My SE instead wants to shift over the block and beam so that the inner section of the 300mm basement walls provide structural support for the floors, rather than the blockwork as shown above. This is going to introduce a bridge to the insulation layer. The SE said if we use the above approach he wants to install steel posts and beams to support the floors above. SE Preference: If we didnt have a basement, and still planned to use block and beam, the beams for the floor would sit on the inner leaf of the block wall anyway. Just because we place a basement wall in does not mean it then has to be used to support the beam/hollow core floor? When we get to the 1st floor we have another block and beam, and for this we have no option but to sit the beams on the inner leaf block work. Which option should we go with? Thank you

I need to commission a soil survey on our plot so that the timber frame/foundation company (probably MBC) can do their calculations for the foundations. Can anyone give me an idea of what the going rate for this should be?