Window to French Doors for Kitchen Extension

[phykell]

Hi,

I'm currently replacing a large window with a set of French doors in a kitchen extension with a flat roof.

The brick is engineering standard and the mortar appears to be concrete as it's incredibly difficult to chisel out. The picture attached below shows what it took my an entire day to do armed with an 850W rotary hammer, club hammer, bolster chisel and air chisel:

http://www.phykell.co.uk/diy/OutsideKitchen.jpg

Don't be alarmed at the one brick stuck in the centre, there's no way it's going to fall down as it's absolutely solid. Removing brick and mortar was like working on solid stone!

Anyway, my main question is that I have a concrete lintel that I will be putting in tomorrow. Is a 150mm overhang on each side sufficient?

My other question is how should I best go about this? I intend to fit the lintel on the outside and then remove bricks from the inside and fit another lintel there. Is this OK?

 

[salem2000]

What did Building Reg Officer advise.

 

[breezer]

although i know zip about building i have to agree with salem2000, you should be seeking professional advice for building work such as you are doing.

we can only offer opinions which may / may not be right in your situation

 

[phykell]

What did Building Reg Officer advise.

I haven't contacted him/her, but I guess you assumed that anyway. So do you think this is something that can/should be tackled by a DIYer? If not, why not?

It's not as if I'm really changing anything, in fact, I'm actually improving what's already there as currently there's only a single wooden lintel for both rows of brick which I'm replacing with two concrete lintels, one for each row. I'll have to do the same with another window in the same kitchen, though I don't have to replace the window, but there's a crack in the external rendering and one on the inside which makes me think I should fit either a steel or a concrete lintel.

 

[masona]

Is a 150mm overhang on each side sufficient?

Yes, 150mm is the minimum.

I intend to fit the lintel on the outside and then remove bricks from the inside and fit another lintel there. Is this OK?

Most builder's do it this way as it's lighter to handle with. What you could also do is, prop up the ceiling with upright timber such as 4"x2" or acrow supporting all the ceiling joists as a safety measure.

 

[tim00]

Q1 are the ceiling joists bearing on the window frame?
Q2 is you new frame the same width as the existing frame?
Q3 there is no sign of a timber lintol. the "soldier course" of snapped headers appears to be sat on the frame head.
Q4 do you realise that you will have to make good both reveals inc. a DPC from top to bottom?
Q5 have you cleared away inside and first fixed to any new design?
Q6 plumb a line at either end of your "render hacking off efforts" from lowest point to fascia. now hack off all the render in that area up to the fascia- first angle grind up the plumb lines to give yourself a clean edge to render to.
note: there are many other points esp. if your new frame reqs. cutting away more brickwork. also have you taken into account how your cill and finished floor will meet and that you will possibly req. a step?

 

[phykell]

Yes, 150mm is the minimum.

Thanks for confirming this. The width of the door set and panel is 6ft combined. I have an 8ft lintel (actually 4" less) which I'll cut down as necessary. I have a 7ft one also for the other side but it turns out it's a metric size and is actually a couple of inches short of 7ft so that's going back as I'd only be able to get 5" on each side, and I'd rather err on the side of caution.

Most builder's do it this way as it's lighter to handle with. What you could also do is, prop up the ceiling with upright timber such as 4"x2" or acrow supporting all the ceiling joists as a safety measure.

The roof of the kitchen is now missing its plasterboard and it's a flat roof of course so there's relatively little weight. Nevertheless, I'm now using a wooden support as suggested until I can get at least one lintel in I should possibly buy a prop for this and future use anyway

Q1 are the ceiling joists bearing on the window frame?

The wall is two bricks thick. The joists sit in the wall for one brick's thickness. The "internal" row of bricks is sat on a wooden lintel which is set into the wall approximately 240mm on each side. The outer row of bricks does indeed sit on the window frame. I'm not happy about this as there are layers of brick on top of this frame, though the wall is so heavily built, that the faces tie in with the internal row. I'm no exaggerating when I say it's like trying to chip away at solid rock!

Q2 is you new frame the same width as the existing frame?

Roughly, yes.

Q3 there is no sign of a timber lintol. the "soldier course" of snapped headers appears to be sat on the frame head.

Yes, that's right. The timber lintel is on the internal row. Is this called a "course" by the way, or is a course, a "layer"?

Q4 do you realise that you will have to make good both reveals inc. a DPC from top to bottom?

I'm above the DPC anyway, but do you mean that the DPC must follow walls vertically?

Q5 have you cleared away inside and first fixed to any new design?

I don't understand the question I'm afraid.

Q6 plumb a line at either end of your "render hacking off efforts" from lowest point to fascia. now hack off all the render in that area up to the fascia- first angle grind up the plumb lines to give yourself a clean edge to render to.

Agreed. I was going to attach a batten temporarily which is the same I guess.

note: there are many other points esp. if your new frame reqs. cutting away more brickwork. also have you taken into account how your cill and finished floor will meet and that you will possibly req. a step?

I've taken into account the cill but admittedly not a step. Can you advise what to do about this? Will it affect the height of the cut-out required or can it just be flush with the opening?

The French doors are from Wickes, the T8 with a side panel and the 8ft cill which I intend to cut down to size.

 

[salem2000]

The reason I asked about Building Control, is if you alter (enlarge) the size of a Window/Door then the Building Control Officer should be involved as it can alter the structual integrety of the building.

It's one thing put a new lintel in, but is it the right one and at the very least Part L of the regulations must be applied to when fitting Doors or Windows.

 

[phykell]

The reason I asked about Building Control, is if you alter (enlarge) the size of a Window/Door then the Building Control Officer should be involved as it can alter the structual integrety of the building.

It's one thing put a new lintel in, but is it the right one and at the very least Part L of the regulations must be applied to when fitting Doors or Windows.

Well as I said, I'm not increasing the width, just the height. I'm replacing a single wooden lintel which only runs across one row of bricks with two reinforced concrete lintels running across each row of bricks and the building is a single floor with a flat roof so I'd say that I'm drastically improving the structural integrity. I take your point though and perhaps not enough people including myself are aware of what should and what shouldn't be checked with a building control officer. I'm not an expert but I think that reasonably speaking, what I'm doing is perfectly acceptable and I've looked through my council's website on building regulations, and others, and it doesn't appear to be a problem anyway. I will bear your advice in mind for any future projects of a similar nature though. Do you know if calling the building control officer costs anything?

 

[masona]

If you pop down to your local building control department, they will give you a free advice, normally you don't have to make a appointment but ring them just incase.

 

[breezer]

If you pop down to your local building control department, they will give you a free advice, normally you don't have to make a appointment but ring them just incase.

isn't that what i said several posts ago?

 

[tim00]

further suggestions: yes" a course" is the building trade name for , a row or a layer.
- the width of your finished opening must be at least 10mm wider than your frame.
- yes, a vertical DPC is necessary on both reveals(sides).
- you dont have much exposure above your frame head but usually a cavity tray is reqd. above openings in brickwork.
- to prop your ceiling joists up merely use a bottom plate the width of the opening, two props-at either end and a top plate.
- given that your plaster board is off, how do you propose to insulate the roof voids as you re-fix the p/b?
- interior preparations should include: re-routing electrics and plumbing
and c/h.re-siting any cabinetwork ie. first fix. all before the break thru.
- the cill must be level with your finish floor and damp proofed to tie in with the original DPC. any step must also tie in with the original DPC or be below it. difficult to advise without seeing job.
- set a drip cap above your frame to throw off water.

 

[masona]

If you pop down to your local building control department, they will give you a free advice, normally you don't have to make a appointment but ring them just incase.

isn't that what i said several posts ago?

Yes but phykell was asking if it will cost anything in his last post.

 

[salem2000]

I'm not an expert but I think that reasonably speaking, what I'm doing is perfectly acceptable and I've looked through my council's website on building regulations, and others, and it doesn't appear to be a problem anyway. I will bear your advice in mind for any future projects of a similar nature though. Do you know if calling the building control officer costs anything?

What is the point of asking for advice if you don't use it

No it will not cost you a penny to call the B.R.O. (apart from the call charge)

 

[phykell]

What is the point of asking for advice if you don't use it No it will not cost you a penny to call the B.R.O. (apart from the call charge)

If you'd posted that I was doing something really terrible then it would be different. The general impression I get is that I'm doing the right thing. I'd love to have the time to speak to the BRO in detail about my project but I work away and have very little time - I have a lot of work to do on this kitchen and the French doors have to be done first. Evidently, I also now have to consider the DPC and other things...

you dont have much exposure above your frame head but usually a cavity tray is reqd. above openings in brickwork.

Interesting. I've not heard about this. I'll look into it.

given that your plaster board is off, how do you propose to insulate the roof voids as you re-fix the p/b?

I've considered this but haven't decided how best to do it. I believe I can get insulation boards. Have you any recommendations?