Loft conversion ridge height
Discussion
I think I know the answer to this but thought I should check.
I'm getting some quotes to do a big dormer to my house next spring. 2 bedrooms and a bathroom.
Of the builders I've had over thus far, all bar one have said that as I've only got just over 2m of head height as it is, then my only option if I want it to feel spacious is to lower the ceilings of the bedroom below. Fair enough they know more than me.
However this adds about three grand to the price. I've walked around my local area quite a bit and noticed some conversions are higher than the ridge, some by a good foot or more. All the builders I spoke to said none of them would have been granted planning permission for this and they should have been built in line with the the existing ridge height. But there are loads of houses with higher roofs! How do they get away with it?
Taking down the ceilings sounds horrendous . We don't have kids but 110 years worth of crap and soot floating through the air. ...
I'm getting some quotes to do a big dormer to my house next spring. 2 bedrooms and a bathroom.
Of the builders I've had over thus far, all bar one have said that as I've only got just over 2m of head height as it is, then my only option if I want it to feel spacious is to lower the ceilings of the bedroom below. Fair enough they know more than me.
However this adds about three grand to the price. I've walked around my local area quite a bit and noticed some conversions are higher than the ridge, some by a good foot or more. All the builders I spoke to said none of them would have been granted planning permission for this and they should have been built in line with the the existing ridge height. But there are loads of houses with higher roofs! How do they get away with it?
Taking down the ceilings sounds horrendous . We don't have kids but 110 years worth of crap and soot floating through the air. ...
It is usually a no no to go above the ridge, plus I think it looks awful. Some local authorities allow it but the planners I've come across don't. You'd need to speak to your local planners. Dropping the ceilings is extremely messy, but so is cutting out for the stairs etc. Just take a long holiday 
princeperch said:
I think I know the answer to this but thought I should check.
I'm getting some quotes to do a big dormer to my house next spring. 2 bedrooms and a bathroom.
Of the builders I've had over thus far, all bar one have said that as I've only got just over 2m of head height as it is, then my only option if I want it to feel spacious is to lower the ceilings of the bedroom below. Fair enough they know more than me.
However this adds about three grand to the price. I've walked around my local area quite a bit and noticed some conversions are higher than the ridge, some by a good foot or more. All the builders I spoke to said none of them would have been granted planning permission for this and they should have been built in line with the the existing ridge height. But there are loads of houses with higher roofs! How do they get away with it?
Taking down the ceilings sounds horrendous . We don't have kids but 110 years worth of crap and soot floating through the air. ...
They are right on all counts as far as I can see. 2m is nowhere near enough. The floor of the loft conversion is usually a completely separate structure from the ceiling below. At best (assuming they can inter leave the floor joist with ceiling joists below) then then the total thickness of the new structure will be around 300-350mm (at the least). Ideally also the new floor structure doesn't touch the ceiling structure below it.I'm getting some quotes to do a big dormer to my house next spring. 2 bedrooms and a bathroom.
Of the builders I've had over thus far, all bar one have said that as I've only got just over 2m of head height as it is, then my only option if I want it to feel spacious is to lower the ceilings of the bedroom below. Fair enough they know more than me.
However this adds about three grand to the price. I've walked around my local area quite a bit and noticed some conversions are higher than the ridge, some by a good foot or more. All the builders I spoke to said none of them would have been granted planning permission for this and they should have been built in line with the the existing ridge height. But there are loads of houses with higher roofs! How do they get away with it?
Taking down the ceilings sounds horrendous . We don't have kids but 110 years worth of crap and soot floating through the air. ...
That said, in this instance, maybe they will just lay in new joists across the lot & attach floor to the top & ceiling to the bottom as per any normal construction. I suppose that might cut 50-70mm or so off the total thickness.
Also, if you take down the ceilings then what ceiling height does it leave below? Am surprised the cost is as little as £3K
Hi,
We are in the final stages of completing our loft conversion on a Victorian Semi in north Herts, We had a ridge height of 2.180mm and to help maintain this height as a minimum there are a couple of things you can do. Firstly use a independent building inspector (very important as they can use code from all over the country not just your local one) for example in North Herts if you use Council building inspectors they require you to change all doors on the escape route to FD30's!!! independent allow you to keep your period doors and use wired and Battery WIFI linked smoke alarms in all habitable spaces.
1. Have the architect spec the ceiling joists be notched into the floor steel rather then having the steel placed on top! this should get you back approx 75mm
2. Independent building control have agreed that we don't have to put the ridge tiles back on! just maintain the ridge line! so we have squared off the ridge line in Lead flashing which has allowed the Ridge steel to sit right up in the top of the ridge line apex giving us back about say 60mm then the builders where cheeky and stole another 50mm as you cant notice it from the street which is where building control looked from!
So all in we have a construction height of approx 2260mm, then you loose approx 20-30mm for plaster board and insulation on the new loft ceiling and a further 40mm loss from the build up of the floor substrates in our case, T&G boards and a final 20mm thick solid oak floor. (you could get the finish floor down to say 10mm using carpet.
Every mm helps and we have a final floor to ceiling height of 2110mm by doing all of the above. Another trick is to cut the doors down from 1981mm to say 1920mm approx to stop it looking like the doors architrave is hitting the ceilings
We couldn't drop the ceiling below as there is a brick dividing wall between the rooms and this is what the floor steel sits on and while we could off removed two courses of bricks and replaced all the ceilings AGAIN! the cost like you state was in our case about 4.5k
Hope this is useful
best
Andy
We are in the final stages of completing our loft conversion on a Victorian Semi in north Herts, We had a ridge height of 2.180mm and to help maintain this height as a minimum there are a couple of things you can do. Firstly use a independent building inspector (very important as they can use code from all over the country not just your local one) for example in North Herts if you use Council building inspectors they require you to change all doors on the escape route to FD30's!!! independent allow you to keep your period doors and use wired and Battery WIFI linked smoke alarms in all habitable spaces.
1. Have the architect spec the ceiling joists be notched into the floor steel rather then having the steel placed on top! this should get you back approx 75mm
2. Independent building control have agreed that we don't have to put the ridge tiles back on! just maintain the ridge line! so we have squared off the ridge line in Lead flashing which has allowed the Ridge steel to sit right up in the top of the ridge line apex giving us back about say 60mm then the builders where cheeky and stole another 50mm as you cant notice it from the street which is where building control looked from!
So all in we have a construction height of approx 2260mm, then you loose approx 20-30mm for plaster board and insulation on the new loft ceiling and a further 40mm loss from the build up of the floor substrates in our case, T&G boards and a final 20mm thick solid oak floor. (you could get the finish floor down to say 10mm using carpet.
Every mm helps and we have a final floor to ceiling height of 2110mm by doing all of the above. Another trick is to cut the doors down from 1981mm to say 1920mm approx to stop it looking like the doors architrave is hitting the ceilings
We couldn't drop the ceiling below as there is a brick dividing wall between the rooms and this is what the floor steel sits on and while we could off removed two courses of bricks and replaced all the ceilings AGAIN! the cost like you state was in our case about 4.5k
Hope this is useful
best
Andy
Edited by aphill80 on Thursday 20th October 15:20
Edited by aphill80 on Thursday 20th October 15:25
aphill80 said:
Hi,
We are in the final stages of completing our loft conversion on a Victorian Semi in north Herts, We had a ridge height of 2.180mm and to help maintain this height as a minimum there are a couple of things you can do. Firstly use a independent building inspector (very important as they can use code from all over the country not just your local one) for example in North Herts if you use Council building inspectors they require you to change all doors on the escape route to FD30's!!! independent allow you to keep your period doors and use wired and Battery WIFI linked smoke alarms in all habitable spaces.
Our independent inspector told us to do this anyway! Lambeth, London.We are in the final stages of completing our loft conversion on a Victorian Semi in north Herts, We had a ridge height of 2.180mm and to help maintain this height as a minimum there are a couple of things you can do. Firstly use a independent building inspector (very important as they can use code from all over the country not just your local one) for example in North Herts if you use Council building inspectors they require you to change all doors on the escape route to FD30's!!! independent allow you to keep your period doors and use wired and Battery WIFI linked smoke alarms in all habitable spaces.
Beautiful glazed period doors kept, and have gone straight back in - we installed cheap as chips FD30 ply blanks to get sign-off.
Stupid rule.
I've done many loft conversions.
I gain 4 inches of head height by using the existing 4 inch floor joists (instead of new 8 inch joists as is the normal specification) and doubling up each joist with C24 4x2s and adding a flitch in the middle as a sandwich. This gives you the strength required but gains you 100mm in head height. No need to lower the floors. All building control and engineer approved.
Get an engineer to draw you up a plan. The flitches tend to be 8-10mmx100mm with staggered bolt holes using single sided TP connectors.
Of course the flitches cost money and so does the extra labour, but head height is everything.
I gain 4 inches of head height by using the existing 4 inch floor joists (instead of new 8 inch joists as is the normal specification) and doubling up each joist with C24 4x2s and adding a flitch in the middle as a sandwich. This gives you the strength required but gains you 100mm in head height. No need to lower the floors. All building control and engineer approved.
Get an engineer to draw you up a plan. The flitches tend to be 8-10mmx100mm with staggered bolt holes using single sided TP connectors.
Of course the flitches cost money and so does the extra labour, but head height is everything.
Mousem40 said:
I've done many loft conversions.
I gain 4 inches of head height by using the existing 4 inch floor joists (instead of new 8 inch joists as is the normal specification) and doubling up each joist with C24 4x2s and adding a flitch in the middle as a sandwich. This gives you the strength required but gains you 100mm in head height. No need to lower the floors. All building control and engineer approved.
Get an engineer to draw you up a plan. The flitches tend to be 8-10mmx100mm with staggered bolt holes using single sided TP connectors.
Of course the flitches cost money and so does the extra labour, but head height is everything.
Are you sure?I gain 4 inches of head height by using the existing 4 inch floor joists (instead of new 8 inch joists as is the normal specification) and doubling up each joist with C24 4x2s and adding a flitch in the middle as a sandwich. This gives you the strength required but gains you 100mm in head height. No need to lower the floors. All building control and engineer approved.
Get an engineer to draw you up a plan. The flitches tend to be 8-10mmx100mm with staggered bolt holes using single sided TP connectors.
Of course the flitches cost money and so does the extra labour, but head height is everything.
When ours was done a new steel frame was built over the existing joists suspended off the walls, then a new floor was build of that in 6x2 (maybe even 8x2, can't remember). The existing joists did not form any part of the structure of the new loft room.
I guess you might be able to take your approach if you're not having a dormer, the steel work on ours is also supporting the roof I suppose.
C0ffin D0dger said:
Mousem40 said:
I've done many loft conversions.
I gain 4 inches of head height by using the existing 4 inch floor joists (instead of new 8 inch joists as is the normal specification) and doubling up each joist with C24 4x2s and adding a flitch in the middle as a sandwich. This gives you the strength required but gains you 100mm in head height. No need to lower the floors. All building control and engineer approved.
Get an engineer to draw you up a plan. The flitches tend to be 8-10mmx100mm with staggered bolt holes using single sided TP connectors.
Of course the flitches cost money and so does the extra labour, but head height is everything.
Are you sure?I gain 4 inches of head height by using the existing 4 inch floor joists (instead of new 8 inch joists as is the normal specification) and doubling up each joist with C24 4x2s and adding a flitch in the middle as a sandwich. This gives you the strength required but gains you 100mm in head height. No need to lower the floors. All building control and engineer approved.
Get an engineer to draw you up a plan. The flitches tend to be 8-10mmx100mm with staggered bolt holes using single sided TP connectors.
Of course the flitches cost money and so does the extra labour, but head height is everything.
When ours was done a new steel frame was built over the existing joists suspended off the walls, then a new floor was build of that in 6x2 (maybe even 8x2, can't remember). The existing joists did not form any part of the structure of the new loft room.
I guess you might be able to take your approach if you're not having a dormer, the steel work on ours is also supporting the roof I suppose.
C0ffin D0dger said:
Mousem40 said:
I've done many loft conversions.
I gain 4 inches of head height by using the existing 4 inch floor joists (instead of new 8 inch joists as is the normal specification) and doubling up each joist with C24 4x2s and adding a flitch in the middle as a sandwich. This gives you the strength required but gains you 100mm in head height. No need to lower the floors. All building control and engineer approved.
Get an engineer to draw you up a plan. The flitches tend to be 8-10mmx100mm with staggered bolt holes using single sided TP connectors.
Of course the flitches cost money and so does the extra labour, but head height is everything.
Are you sure?I gain 4 inches of head height by using the existing 4 inch floor joists (instead of new 8 inch joists as is the normal specification) and doubling up each joist with C24 4x2s and adding a flitch in the middle as a sandwich. This gives you the strength required but gains you 100mm in head height. No need to lower the floors. All building control and engineer approved.
Get an engineer to draw you up a plan. The flitches tend to be 8-10mmx100mm with staggered bolt holes using single sided TP connectors.
Of course the flitches cost money and so does the extra labour, but head height is everything.
When ours was done a new steel frame was built over the existing joists suspended off the walls, then a new floor was build of that in 6x2 (maybe even 8x2, can't remember). The existing joists did not form any part of the structure of the new loft room.
I guess you might be able to take your approach if you're not having a dormer, the steel work on ours is also supporting the roof I suppose.
I don't know of anyone else that uses this approach. It is designed to take the load of a dormer, in conjunction with using 3x 152x152 section steels and a ridge beam of course. The two outer steels have the dormer walls sitting on them so you don't lose head height because of them. The centre steel has the flitched beams sitting within the webbing and going 50cm into the spline wall below.
Another thing I do is to splice all my steels 2 thirds 1 third. This means you don't need a crane to haul the steels in nor do you need to chop a hole in the roof to get them through, nor chop extra bricks from the party wall to squeeze them in.
If the height is only 2m at present then I can't see how using smaller joists really helps, its already at the bare minimum head room for a completed loft. Even if the existing floor wasn't raised,(unlikely) height will still be lost due to ridge beam, roof joists and insulation. I'm not exactly tall and my loft is 2.1m, I wouldn't want it any lower than that, 2.0m is the height of a standard door, too low for a ceiling imo . If the starting height is 2m then the finished height will be 1.7/1.8m ish which is way to low for regs and practicality.
Little Lofty said:
If the height is only 2m at present then I can't see how using smaller joists really helps, its already at the bare minimum head room for a completed loft. Even if the existing floor wasn't raised,(unlikely) height will still be lost due to ridge beam, roof joists and insulation. I'm not exactly tall and my loft is 2.1m, I wouldn't want it any lower than that, 2.0m is the height of a standard door, too low for a ceiling imo . If the starting height is 2m then the finished height will be 1.7/1.8m ish which is way to low for regs and practicality.
Yep. Looks im stuffed and the ceilings will have to come down.Dropping the ceilings does have other advantages, you'll get nice new level and flat plasterboard ceilings which offer the required fire resistance without a fire quilt, the stairs will be more compact, as say you drop it 450mm you'll need 2 less treads/risers to get up there, that can be a quite important on a small loft.
I'll have To concentrate on the positives. I must admit I was a bit sad when he said it would be about another three grand bringing the total projected cost to 48kish.
That three k is almost exactly what I was going to spend upgrading my 300 quid almera when the loft is finished next year. Looks like Ill be spending a bit more time smoking about in the old girl yet!
That three k is almost exactly what I was going to spend upgrading my 300 quid almera when the loft is finished next year. Looks like Ill be spending a bit more time smoking about in the old girl yet!
Little Lofty said:
If the height is only 2m at present then I can't see how using smaller joists really helps, its already at the bare minimum head room for a completed loft. Even if the existing floor wasn't raised,(unlikely) height will still be lost due to ridge beam, roof joists and insulation. I'm not exactly tall and my loft is 2.1m, I wouldn't want it any lower than that, 2.0m is the height of a standard door, too low for a ceiling imo . If the starting height is 2m then the finished height will be 1.7/1.8m ish which is way to low for regs and practicality.
+1It's bad, rooms will have to be completely emptied, carpets lifted etc. The bathroom is also a sticking point if it's in the affected area, lots of upheaval, re-tiling possibly. It's not just the ceilings that come down, the walls have to be lowered too. It's not something I would have ever attempted in a house where the customer was living. I might start doing lofts again, I used to charge £25k for a bedroom with ensuite and an extra £3/4K for a large dormer, I'll do yours for £47999 
Gassing Station | Homes, Gardens and DIY | Top of Page | What's New | My Stuff