ETC

Will the thermal loss be any greater than through the adjoining window?

Build a 100mm thick block wall either inside or outside the building.................then build whatever you want!

...................Or.................put plywood over the joists and then tapered firing pieces from front to back.

I do believe that the steelwork should be fire protected within a domestic floor where it supports an element of structure above - in this case a cavity wall. I don't think your BCO is correct if he/she is saying that simply enclosing the beams in the floor will give the fire protection.

I presume there is a roof not a floor above this?

Search the Register This might help.

If it’s within 1m it needs to be substantially non-combustible material. Timber frame on its own with metal cladding won’t give you the FR you need. The rules for FR for a building within 1m require the wall between you and your neighbour to have 1HRFR and that needs to be from BOTH SIDES. More than 1m away and the FR is required from INSIDE only.

There are a hundred and one ways to skin a cat but only one set of Regulations - often open to interpretation - as long as you comply with the Regulations youare home in a boat.

Your BCO should be asking for all structural steel in a two and three storey dwelling to be fire protected to achieve 1/2HRF - simplest way is to paint with intumescent paint. Boarding requires a tested detail from British Gypsum to be followed. Sticking two layers of fire line board might do the trick but I doubt BG would sanction the construction.

You won’t find that specification on Google!

I think Elvis has left the building!

It’s a Visqueen product and is - I’ve been told - radon proof. Easiest way to install a radon barrier is to: Build up your sub-floor blockwork to the underside of your slab level. Fill voids between rising walls and finish off with well compacted hardcore and 50mm of blinding. Lay a 1200 gauge membrane (minimum gauge for a radon barrier) over the complete footprint of the works. Overlap and tape all joints. Use top-hats for services. Set up a 150mm slab complete with anti-crack mesh and bear the slab 100mm onto the sub-floor blockwork. Pour the slab. Put a stepped DPC around the perimeter of the slab.

In all honesty I think you need to appoint a good architect. Not an architectural designer - an architect who knows how to build, design and who knows the Building Regulations. I get the impression that you are not content with what your own designer has come up with otherwise why would you ask for feedback from an anonymous internet forum. If you have been advised that you need fire doors downstairs and a wacking great big void to below is acceptable you’ve been misled. A two storey dwelling doesn’t need fire doors unless you are creating a protected staircase and why go to the expense or inconvenience of doing so if you don’t need to. I do think you are missing a trick - a great architect will create a building which is a joy to live in rather than just individual spaces. You could have had an atrium in the middle with courtyard (like many Mediterranean houses) or used the shell of the building as just a shell and created a series of buildings within the shell. I am by no means a fantastic architect but I do consider myself to be pragmatic and practical perhaps to the extent of boring but I can recognise talent and to be honest I don’t think your proposal is the best it could be. I’m also fairly versed in the Building Regulations although in my UK region we are slightly behind England - we would be less flexible in relation to fire control. Don't get triggered - the members here are genuinely interested and have offered some - largely - practical advice. Good luck and I hope you get sorted.

Yes they do.

Might be cheaper to get someone who knows how to use CAD to draw it for you.

The gutter is too low and falling towards the building. Raise the gutter to the underside of the flashing.

Vary the bed depth.

No. If the steelwork requires FR speak to British Gypsum or Harmon for the correct way to fire protect steelwork.

Have to agree. Organ grinder and monkey come to mind. No offense.

No.

Should have been two beams. You'll also need a stepped DPC/cavity tray above the beam.

Did not know that…….good to know about mould……

Nope. Does the same job. Just need to undercut the doors to allow for whole house BV.

Just look at the legislation-it will say what the inspections are.

Install a roof light where you need the head room. You’ll get an extra 100mm easily.