Dealing with Local Building Control for French Doors

FreeBear

Owain_Moneysaver said:  Once you've made the opening, you can have a stud wall in front of the existing wall and sliding/pocket doors (although that restricts the opening to less than 1/2 the wall width as the doors need space to retract). 

You don't have to go sideways. There is always the option to go up or down - https://www.bbc.co.uk/news/av/uk-england-devon-21661850/disappearing-wall-at-coombe-trenchard-manor-in-devon

As others have pointed out, knocking an opening through a load bearing wall needs BC approval. Without it, selling the property may prove to be more difficult and incur additional costs.

bigpappa

Owain_Moneysaver said:

1. You need a Building Control application and appropriate fee. 
2. You need a lintel.
3. Building Control must approve the lintel calculation.
4. Many supplies of lintels (structural steel suppliers) will do a simple lintel calculation for you free or very cheap when you buy the lintel, which will be accepted by Building Control. Otherwise you may need a structural engineer.

Remember that although the lintel supports the weight of the wall above, it can only do this by transferring the load to the walls on each side of the opening, so the walls and foundations at each side have to take the point load which was previously evenly spread along the wall length. 

You can have whatever size of opening you want but it will be significantly more expensive if you want the walls or ceiling to be flush across the division. You can have a central door or door with fixed side lights. 
Once you've made the opening, you can have a stud wall in front of the existing wall and sliding/pocket doors (although that restricts the opening to less than 1/2 the wall width as the doors need space to retract). 

So a concrete lintel is out of the question?

bigpappa

FreeBear said:

Owain_Moneysaver said:  Once you've made the opening, you can have a stud wall in front of the existing wall and sliding/pocket doors (although that restricts the opening to less than 1/2 the wall width as the doors need space to retract). 

You don't have to go sideways. There is always the option to go up or down - https://www.bbc.co.uk/news/av/uk-england-devon-21661850/disappearing-wall-at-coombe-trenchard-manor-in-devon

As others have pointed out, knocking an opening through a load bearing wall needs BC approval. Without it, selling the property may prove to be more difficult and incur additional costs.

Thats a good point. But then how would you know what work has been done and not?

Doozergirl

bigpappa said:

FreeBear said:

Owain_Moneysaver said:  Once you've made the opening, you can have a stud wall in front of the existing wall and sliding/pocket doors (although that restricts the opening to less than 1/2 the wall width as the doors need space to retract). 

You don't have to go sideways. There is always the option to go up or down - https://www.bbc.co.uk/news/av/uk-england-devon-21661850/disappearing-wall-at-coombe-trenchard-manor-in-devon

As others have pointed out, knocking an opening through a load bearing wall needs BC approval. Without it, selling the property may prove to be more difficult and incur additional costs.

Thats a good point. But then how would you know what work has been done and not?

Most houses weren't built with double doors between rooms.   Of course it depends on the period of the house and also on the last time your house was sold as there are historic photos online of a lot of houses.  

The key point isn't the house sale, though, it's ensuring your own safety.  

Owain_Moneysaver

bigpappa said:

So a concrete lintel is out of the question?

Not necessarily, but you'd need a calculation to prove it. 

weeg

Owain_Moneysaver said:

bigpappa said:

So a concrete lintel is out of the question?

Not necessarily, but you'd need a calculation to prove it. 

You need a calculation to prove whatever lintel you use. Both steels and precasts have standard load bearing capacities, and both need a min 150mm bearing either side. You can, theoretically, do the calculation yourself. There are standard loads in the design standards (eurocode 1, part1), and you figure out what is sittting on the wall (so, roof? wall above? first floor?).
In a brick internal wall, my go-to is a robeslee concrete lintel. They come in 300mm increments, and it's REALLY unlikely that a type C won't do the job. (there are loads of other manufacturers, but the idea is all the same) BUT building control will have to ok it.
(FWIW, I'm a domestic structural engineer, but I  work in Scotland where the BC regime is totally different and way more onerous)

bigpappa

weeg said:

Owain_Moneysaver said:

bigpappa said:

So a concrete lintel is out of the question?

Not necessarily, but you'd need a calculation to prove it. 

You need a calculation to prove whatever lintel you use. Both steels and precasts have standard load bearing capacities, and both need a min 150mm bearing either side. You can, theoretically, do the calculation yourself. There are standard loads in the design standards (eurocode 1, part1), and you figure out what is sittting on the wall (so, roof? wall above? first floor?).
In a brick internal wall, my go-to is a robeslee concrete lintel. They come in 300mm increments, and it's REALLY unlikely that a type C won't do the job. (there are loads of other manufacturers, but the idea is all the same) BUT building control will have to ok it.
(FWIW, I'm a domestic structural engineer, but I  work in Scotland where the BC regime is totally different and way more onerous)

Thankyou for your input and advice. Whats sitting above it is another wall and then the roof space but the roof space is not supported by the wall in the first floor.

Well the thing I would like to do first is work out the costs before proceeding - so can I just price up by length of opening and go for the lintel that can take the most load?

I am just wondering whether I can find the lintel that can take the most load and apply and worst comes to the worst then ask for a SE to OK it if the BC do not agree.

bigpappa

weeg said:

Owain_Moneysaver said:

bigpappa said:

So a concrete lintel is out of the question?

Not necessarily, but you'd need a calculation to prove it. 

You need a calculation to prove whatever lintel you use. Both steels and precasts have standard load bearing capacities, and both need a min 150mm bearing either side. You can, theoretically, do the calculation yourself. There are standard loads in the design standards (eurocode 1, part1), and you figure out what is sittting on the wall (so, roof? wall above? first floor?).
In a brick internal wall, my go-to is a robeslee concrete lintel. They come in 300mm increments, and it's REALLY unlikely that a type C won't do the job. (there are loads of other manufacturers, but the idea is all the same) BUT building control will have to ok it.
(FWIW, I'm a domestic structural engineer, but I  work in Scotland where the BC regime is totally different and way more onerous)

I have just looked at the price of a robeslee concrete lintel and its about £20 for 1500mm or £25 for 1800mm.

That seems very cheap? I was looked at a Catinic BXD100 which are about x4 the price - but I really don't mind payng the price for the best product because I am sure a branded product once I put in the BC application I assume they would know more about?

weeg

bigpappa said:

weeg said:

Owain_Moneysaver said:

bigpappa said:

So a concrete lintel is out of the question?

Not necessarily, but you'd need a calculation to prove it. 

You need a calculation to prove whatever lintel you use. Both steels and precasts have standard load bearing capacities, and both need a min 150mm bearing either side. You can, theoretically, do the calculation yourself. There are standard loads in the design standards (eurocode 1, part1), and you figure out what is sittting on the wall (so, roof? wall above? first floor?).
In a brick internal wall, my go-to is a robeslee concrete lintel. They come in 300mm increments, and it's REALLY unlikely that a type C won't do the job. (there are loads of other manufacturers, but the idea is all the same) BUT building control will have to ok it.
(FWIW, I'm a domestic structural engineer, but I  work in Scotland where the BC regime is totally different and way more onerous)

I have just looked at the price of a robeslee concrete lintel and its about £20 for 1500mm or £25 for 1800mm.

That seems very cheap? I was looked at a Catinic BXD100 which are about x4 the price - but I really don't mind payng the price for the best product because I am sure a branded product once I put in the BC application I assume they would know more about?

They are cheap - that's why they are so widely used. Even a non-branded one should have a declaration of performance with a load capacity.  I can't think of any advantage you would gain by using a steel. Are you absolutely sure the first floor doesn't sit on the wall? If it's just a wall over then the load is pretty minimal (like 30kg). But don't take my word for it, as I've never seen your house.

bigpappa

weeg said:

bigpappa said:

weeg said:

Owain_Moneysaver said:

bigpappa said:

So a concrete lintel is out of the question?

Not necessarily, but you'd need a calculation to prove it. 

You need a calculation to prove whatever lintel you use. Both steels and precasts have standard load bearing capacities, and both need a min 150mm bearing either side. You can, theoretically, do the calculation yourself. There are standard loads in the design standards (eurocode 1, part1), and you figure out what is sittting on the wall (so, roof? wall above? first floor?).
In a brick internal wall, my go-to is a robeslee concrete lintel. They come in 300mm increments, and it's REALLY unlikely that a type C won't do the job. (there are loads of other manufacturers, but the idea is all the same) BUT building control will have to ok it.
(FWIW, I'm a domestic structural engineer, but I  work in Scotland where the BC regime is totally different and way more onerous)

I have just looked at the price of a robeslee concrete lintel and its about £20 for 1500mm or £25 for 1800mm.

That seems very cheap? I was looked at a Catinic BXD100 which are about x4 the price - but I really don't mind payng the price for the best product because I am sure a branded product once I put in the BC application I assume they would know more about?

They are cheap - that's why they are so widely used. Even a non-branded one should have a declaration of performance with a load capacity.  I can't think of any advantage you would gain by using a steel. Are you absolutely sure the first floor doesn't sit on the wall? If it's just a wall over then the load is pretty minimal (like 30kg). But don't take my word for it, as I've never seen your house.

Yes first floor sits on the wall. Its a terrace, two rooms up, two rooms down. The wall that I am thinking of putting in double doors is supporting the wall above in the first floor.

I just thought steel trying to look at what can take the most load?

All the builder mentioned was its a pre stessed conceret lintel - is it better to go with reinforced?