Cutting doorway in load-bearing wall

Hi
Never done this before, but I want to put an internal doorway in a wall which is obviously load-bearing. 1900's brick built. Being of a cautious disposition I want to look into this in great detail before doing anything...
So where do I start? Obviously I need to fit a lintel and will have to play with acro props, but could someone maybe point me in the right direction? I was advised by someone to get myself a Stihl saw to rip up the brickwork - ie much easier than hammer and chisel - but am not sure what this is. Is it a regular circular saw (already have one) but with a fancy blade?
Thanks!! David
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Catnic and IG websites have outline info on lintels, props are cheap to hire, look into strongboys for the props - makes life so much easier. Might be worth chopping away at the plaster in places as it can help line up the cut so as not to leave too many thin brick ends which will have a habit of falling out anyway. Depending on how large a hole you are considering and the load to be supported, a UB (universal beam, modern version of an RSJ) may be required. Pay attention to the end bearing surfaces for the lintel, these should be 150mm or greater each and be on good quality material. Dryish mixed mortar should be packed/rammed under the beam.
If it's only a single door rather than double, and the brick is only single width it should be an easy job. You can hire a stihl saw, http://www.toolshopdirect.co.uk/ishop/982/shopscr1388.html but I have done the same job with a 9" grinder down both sides. Your brick wall will break down very easily, once you get started, the original 1900 mortar will just drop off. You need to exercise a little caution as the hole can tend to 'spread' if you go at it too enthusiastically.
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A saw will produce one hell of a lot of mess. Knock the bricks out one at a time. Once you get the first loose, they will come out like plastic teeth. Get a saw as a last recourse. And a load of dust sheets.
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You start by getting a good structural engineer to design the load bearing properties of the lintel and surrounding wall. Because you place a lintel in the wall, it doesn't mean the rest of the existing wall will be able to take the weight on the smaller area that the lintel presents.
You'll also most likely need to have planning consent before making changes to structure of the property. The skeleton of the house is going to be changed, so the planning and building control people will need to kept in touch with the changes being made.
The lintel may have to be longer than you think to spread the extra weight across more the existing wall, so be very careful, please.
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changes
Building Control - yes. Planners - no, unless the external appearance or use to which the building is put are affected by the new doorway. My understanding is that this is in an internal wall - so I think the planners need to be involved.
Roger
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1. Buy a lintel. a) if wall is two bricks thick (9") then a 4' long by 9"x8" concrete should do. b) or box section steel Phone a local builders merchant or two to get prices and sizes, they do this all the time.
2. Cut hole for lintel. Collins DIY book says that for small openings props are not always needed.
3. Insert lintel in hole, bedding ends in strong cement mix. You'll need someone to help you lift it into place. Replace any bricks that fell out when making hole for lintel.
4. Cut out hole for doorway. Any saw will make a LOT of dust. Perhaps buy a door lining kit from Wickes etc. first to get size of opening required.
5. Fix door liners etc.
It's not rocket science. I've just put a lintel in where there the UPVC double glazing has been supporting three first floor joists for the last 20 odd years and another where an upstairs window lintel was only supported at one end i.e. for small openings the rest of the brickwork gives a lot of support.
I strongly recommend you buy the Collins DIY maual - lots of useful info on lots of projects. I think building control is a bit overkill. If you are worried phone a structural engineer to come and look.
Neil
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Sorry, but this is extremely irresponsible and dangerous advice. We don't know the wall thickness, the span of the opening or the load to be supported. We don't even know whether it's an internal or external wall or whether it's solid or cavity. I find it extremely alarming that people feel they can give advice like this when they obviously know nothing or very little about Planning law or Building Regs, or about structural design. I hope beyond hope that nobody takes it seriously.
I was once called to sort out an emergency where someone had been given wrong advice similar to this. He had put in 3 Strongboy props and cut a 3m wide opening in a 225mm brick wall. What he didn't realise was that the wall was supporting a 30-Tonne water tank! When I got there the props were bow-legged under the load and the wall had a massive fracture and was leaning outwards! We had to evacuate the building (5 storeys of flats), drain the tank and put in loads of new props and shoring to make it safe. I think they had to completely rebuild the wall and renew part of the roof. He was found guilty of contravening the Building Regulations and of endangering life under the H&S at Work etc Act. He could so easily have killed himself and many others too!
Building Regulations permission is DEFINITELY required for any structural alterations. The reason for this is prevent cowboys and DIY-ers making stupid mistakes like this. If you don't know what you're doing then talk to someone who does.
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That's why I suggested he call a few builders merchants.
I find it extremely alarming that people feel they can give advice

The original poster was intelligent enough to ask here before starting work so I give him credit for knowing whether or not he has a 30 ton water tank somwhere in his house.
When I got there the props were bow-legged

Yeah, yeah, yeah. I repeat, that's why I suggested he ... oh why bother... Neil
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Niel A. Farrow wrote

know
solid
Builders Merchants don't do structural calculations. The correct advice is to call a Structural Engineer

Where does it say it is a house? How many storeys are there above this wall?

Please Neil, all I'm saying is that anyone giving advice should know what they're talking about or, to put it another way, if you don't know what you're talking about then don't give advice! For this very reason I don't give advice on electrical questions for example.
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I've been following the discussion with interest!
I can appreciate that Building Control is a must, and will certainly call them in (I already need them to inspect other stuff I'm doing anyway).
Whilst not disputing for a moment that involving a structural engineer is the *correct* thing to do - consider what would happen if I engaged a local builder to do the job? Give that this is a straightforward job, I've no doubt that he would size it up, scratch his chin then specify and fit the necessary lintel needed. If I do engage a structural engineer to do this, I imagine it will cost almost as much again as the builder; so on that basis, d-i-y is not a viable option.
My job is an ordinary 3.5 foot doorway in the middle of a ground floor, internal wall, brick-built, two bricks thick. The wall concerned goes up to ceiling level on the 1st floor. It's a standard 1900's 2-up-2-down terraced house, (no 30-ton water tanks hidden upstairs!)
If I were to fit a lintel (having established what size with info gleaned from manufacturers' websites, builder's merchants, this ng, and Collins DIY manual!, which surely isn't rocket science) and then have it inspected by building control before plastering up, wouldn't that be adequate?
Please note I certainly haven't decided not to consult a structural engineer; just want to be sure it's necessary!
Thanks David
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IME you shouidl expect a bill of 100-150. How much will the builder cost?

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I was expecting it to be more like about 150-200; ie about 2 days' worth of a builder's time, which should be more than enough time? (But I have no doubt that I'll have real problems finding someone to take on such a footling job; another reason for the diy route...)
David
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Lobster wrote:

Talk to the Building Inspector ASAP. If he's as helpful as those in my area he'll tell you what you need to do to satisfy building regs - probably including what size lintel you need. If the whole thing is less than straightforward (which it doesn't seem to be) he'll also tell you what calculations he'll need to see to back up the design. In this case, you *would* need a structural engineer, but otherwise it may not be necessary.
--
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don't
We
to
wall?
you're
advice
OK David, now you've outlined the situation it's easier to give sensible advice.
I agree with SetSquare - talk to your BCO before doing anything else. You'll need to submit a Building Notice with a fee. Tell him what you are planning and he will guide you through. If he needs data or calculations to back up the choice of lintel then you'll probably need a Structural Engineer to work out the loading.
But if the loading is "normal domestic" and the brickwork is in reasonable condition then the BCO will probably accept a lintel selected using manufacturers' data for safe working loads for given spans. I would suggest using a prestressed concrete lintel 215mm wide, either one or two brick courses deep. That would be cheapest and easiest for you to install. I'm not sure what Collins DIY manual has in the way of lintel data, but you can phone up manufacturers or ask builders merchants for leaflets or look on the web. There's a lintel selector on this site: http://www.naylorlintels.co.uk/index.asp
For a clear opening of 1000mm a Naylor type ER4 Economy lintel 215 x 65mm (about 15 from any builders merchant) will safely support an unfactored load of 8.76 kN/m. I can't say whether this is adequate in your case but I expect so. Also check the bearing stress on the brickwork based on 100mm bearing length each end (21,500 mm) - it should not be greater than say 5 N/mm. If the brickwork is soft or weak the bearings might need to be increased to 250mm (the next lintel length).
For short-term support for the new opening, you only need to support the weight of a 45 triangle of wall above the opening. One support in the centre should be adequate. A Strongboy would do it but this would need solid support at the bottom and timber floorboards may not be strong enough. I think you can hire a smaller type of prop (like a letter C) which supports the wall above the lintel on the wall below. HSS call this a Jackall Wall Support. You insert it into two brick joints to enable you to insert the lintel before you pull the wall down. I'd use one each side on a 215mm wall.
I wouldn't use a Stihl saw - as has been said, it will make a hell of a mess. If the bricks are too hard to cut out by hand then use a Kango or SDS drill to start the job off then you can knock the remaining bricks out with a club hammer. You may need to make good the sides of the opening with pieces of brick cut to fill the gaps. You don't say what the floor construction is - take the wall down to below floor level and don't forget you may need to replace the damp-proof course.

I hope I've answered this now! Come back to me if you don't understand anything.
Peter
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I certainly think so - many thanks to you and the other responders. I'm not likely to be tackling this for a few weeks yet but I'll let you know how I get on...! David
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