Taking out wall between house and extension

[CakeThat]

We've had plans drawn up for an extension across the back of our house. This is to be a second living room with bifold doors onto lawn. The person who drew up our plans said that this would fall under the rules of permitted development. He also said that we would need to keep our existing external patio door between the house and the new room. When I questioned why I was told that this was because of rules relating to emissions. He said that if you wanted to open up the space by removing the doors to create an opening this would not fall under permitted development and would be tricky to get past planners. I have since been to other people's houses where the whole wall was taken out between the existing house and the extension and I've decided that this is what I want to do. Builder says that everyone does this nowadays and it should be no problem as the extension is a proper room and will be insulated to current standards. He thinks you only need to keep external doors for structures such as conservatories which are not habitable. Can someone tell me who is right and if I want to take down the wall will I have to get plans redrawn and reapply for full planning permission?

Don't know about the regs about this but, one way around it. Have the extension done, leave the doors in, if you need it signing off, get it signed off then, remove the doors and get a plasterer in to touch it up. No-one will be any the wiser.
Just an idea.

Ha thank you yes the person who did the plans did suggest doing that. Only problem is that we are hoping to fully take out the wall between the house and extension, which presumably would need overseeing by building regs.

What structural measures are being taken?

That back wall will be a load bearing wall and you most certainly will need building regs for it. To be honest it sounds like the person drawing up the plans isn't that up to date with anything - see if your council planning dept has a drop-in clinic where you can get an idea of whether you'd need PP as well as building regs. Worth spending the extra time and money to get it right or it will be a nightmare when you come to sell.

If the wall was external, the patio window and door would form part of the structure holding up the wall.

If there are no plans to put in steel joists with padstones, then you would do well to investigate what's holding the wall up before you follow Zombiepigman's suggestion, otherwise the wall could be structually unsound and at risk of collapse.

As I understand it, you will need building regs regardless of keeping wall or not, and planning permission only if you've extended before, you want to go out further than allowed under PD, go closer to a boundary than you're allowed or if you're going double storey. Of course this may only be relevant to my area so apologies if that isn't correct.

FWIW, we went out just over 3m from back of house (double storey so did need PP) but took out back wall of house completely (and also wall which divided dining room and kitchen). It comes down to how you live your lives but it works so well for us, leaving existing structure up / patio doors or whatever would (in my view) have looked really odd. Have space of around 7m x 7m and although its a bug space with lots of glass (velux, bifolds, big window) it is much warmer than back of house used to be as its all been properly insulated / radiators places strategically etc.

Just to clarify. If you already have patio doors in, there will already be a RSJ in place so, removal of the patio doors would be straight forward.

Another way around it. Again, get the extension finished then, few months later, get the builders back in, install a RSJ and remove the wall on the QT.

We chose not to do this as it was going to cost a fortune (ca. £10K) with a huge steel and the need to build some substantial foundations. Have kept the original openings and opened up as much as we can get away with and it's still very good.

Yes we will definitely be consulting a structural engineer and doing it all above board, I'm just curious to know why the first guy said that we had to keep our external doors and what the implications are for our planning application now that we have decided not to. Maybe I'll call the planning dept in the morning. Thanks for all the advice!

If I remember correctly the cost of planning is £170 - we have had an extension done recently and while the guy drawing the plans said it would fall within permitted development he recommended going for planning so that when we sell we have a clear paper trail. You need building regs and structural calculations regardless. So with planning you can be sure of if the door needs to be there or not.

The planner will be right if it is a conservatory, garden shed, greenhouse or other construction that is not considered to be part of the house and is not properly insulated. This is to prevent energy wastage by heating the sky.

If it is a genuine extension with walls and a roof, not made of glass, you would not need the doors.

Thanks yes it is an extension with walls and roof. I vaguely remember he said something about the bifold door size being more than 25% of the floor area which apparently is an issue. The doors are only 2.5m wide though, hardly grand designs!

We hit that over 25% rule too - building regs (and its them who care about thermal efficiency, not planning) agreed we could offset the large amount of glass with other measures in the house - thicker loft insulation, long life light fittings, decent u value for the glass we installed.

I think the guy doing your plans has got confused. As others have said, it's not a planning thing but a building regs one.

Be careful with your opening up of the house. I had a job recently with a 6m wide opening and I needed to put in steel posts as well as beams (and enlarged foundations for the posts too). It was really quite a lot of work. Can be worth it but make sure you're happy with it. And also remember that whenever you do new openings, particularly if they're big, you're likely to get some settlement and cracking in the walls above.