knocking out wall

markyyyyyy · 27 Jun 2017

Hi,

just a after a bit of advice

i have been quoted £300 to knock out a 900mmx 2100mm opening in a wall that separates our kitchen to dining room. This wall is a single skin (just one standard size brick) supporting wall that runs from downstairs to upstairs.

I am toying with the idea of doing it myself - is this pretty straightfoward? In terms of the Lintel position, am i correct in saying that i would need to cut out the equivalent of one brick and the adjoining mansory in the brickwork to fit the concrete lintel (http://www.wickes.co.uk/Wickes-Steel-Reinforced-Concrete-Lintels/p/9000038435) BEFORE cutting the brick opening?

When i fit the concrete lintel, do i just position is in place and fill the gaps with mortar mix?

The steps i would take are below:

step 1: Cut out masonry and one row of bricks to the correct width for the concrete lintel
step 2: Use a disc cutter to cut out the outline of the door opening once lintel and mortar has dried
step 3: use a sledge hammer to knock out the bricks for the opening
step 4: replaster the door frame as probably just going to have it as an opening rather than a door on it.

Or .... would you feel that £300 is a pretty reasonable price for the work involved?

I am a pretty handy DIY'er but have not knocked down a wall before.

Thank you!

garyo · 27 Jun 2017

Sounds like a good price if that involves cleaning up and making good. If this is a house that you're living in then the mess from using a disc cutter will be grim.

markyyyyyy · 27 Jun 2017

thanks for your reply. Yes, it is a house we live in ... and we have just recently had new carpet fitted ... however my wife is 20 weeks pregnant and we really need this door so she can see the baby while in the kitchen! talk about inconvenient timing hey!

Forgot to say, the price is just for knocking out the brickwork and installing the lintel... everything else i am going to do myself (apart from moving the electrical sockets etc in the kitchen!)

honda · 27 Jun 2017

If it's a supporting wall what's it supporting?

markyyyyyy · 27 Jun 2017

good question - i don't know.... but my friend is a building surveyor and when he was over last year he mentioned its a supporting wall.... but i didn't ask what it is supporting.

Doggit · 27 Jun 2017

It'll be supporting the wall above it.

If your handy DIYer, and feel confident, then it's not a difficult job, just dusty. For a 900mm opening, you'll need to use a 1.2m lintel, and be aware that they're only 65mm high, so you pack them up from underneath on either side of the opening - Wickes gives the height as 100mm, but that's actually the width.

You could use a strongboy on an acrow to support the bricks above the opening (cheap to hire from a local hire shop), and that'll stop too many bricks from dropping.

A disc cutter is going to make a hell of a mess, so bolster and hammer, with the assistance of a crowbar, is slower, but cleaner. Leave it a couple of days after setting in the lintel, and the concrete will have gone off nicely before you start disurbing it with a sledge hammer. And see if you can get hold of an old slate, as it's good for packing gaps betwen the bricks and the lintel etc. Use a dryish mixture of cement to cut down on the shrinkage, and you should be fine.

markyyyyyy · 27 Jun 2017

thank you for your help.

What do you pack underneath the lintel with?

so would you knock out the bricks where the lintel is going to be, before knocking out the main opening where the wall is? Or would you knock all of the bricks out before installing the lintel? At what point would in the 'demolision' would i i use the strongboy on an acrow?

I am confident at giving anything ago, so i think it will be fine.

Thanks again

Mark

Doggit · 27 Jun 2017

You first take out the row of bricks where the lintel is going to go. Now if you're lucky, none of the bricks above will have fallen down, you'll put the lintel in place, and use the slate underneath it to push it upwards, and then pack in the cement, and you'll also use bits of slate to pack any gaps beween the lintel and the bricks above.

But, if you think that the bricks above will drop, then you play safe and put a stongboy a couple of rows further up before you cut out the row for the lintel. You cut out a lenth of the mortar, slide the strongboy in place, and that supports the brickwork. Having said all that, as the lintel is only 1.2m, you could very likely ignore the strongboy, and just relay any dropped bricks once the linetel is in place.

The main opening gets done once the lintel is securely in place. Now it's more than likely that the builders would cut the opening, put the lintel in place, and then sort out any dropped bricks afterwards, but that's confidence in knowing what you're doing.

markyyyyyy · 28 Jun 2017

many thanks for your help.

my wife has suggested a narrow walk through, due to kitchen space. I note that wickes do a lintel that is 600mm long .... if i were to use this, what is the maximum width of a doorway that would be suitable? Would 5cm hangover each size be sufficient, or is it a minimum of 10cm each side for the lintel, regardless of the width of the opening?

Daft question, but would old scraps of slate roof be okay to wedge under the lintel?

Cheers

Mark

Ian H · 28 Jun 2017

I've done this as a diy'er.

To install the lintel I drilled out the mortar from 2 sides of one brick then gently knocked it out. Then for the rest of the bricks I just drilled out the mortar from under the brick then it easy to push then out.

I did 2 rows, stuck in a 140x100 concrete lintel and mortared it up.

Next day I took out all the bricks for the opening and knocked off the left over half bricks with a wide bolster.

I used a hoover while drilling and **** myself once a few bricks were out but nothing above it moved or fell out.

Doggit · 28 Jun 2017

Because it's a supporting wall that you're working on, you want a minimum of 100mm either side. If you do the job properly, then you won't have any issuses in the future, but with a 500mm opening, it'll cause problems when you come to sell it. A door would normally be about an 800 opening, so maybe aim for a door width, and then one can be added at a later date if necessary. If you need to cut the lintel, then you can use an angle grinder with a stone blade, as that'll go through the steel as well as the concrete.

When you break a slate, you normally end up with scraps anyway, so they'll be fine.

Edit: Ian used a drill, but you could use a mortar rake to get the bricks out even easier.

garyo · 28 Jun 2017

A 700 door doesnt look too bad either especially if the room is small.

Doggit · 28 Jun 2017

As in 800 opening, add door lining, and you'll end up with a 700-750 door.

garyo · 28 Jun 2017

Yes - fair point.

Gerrydelasel · 29 Jun 2017

I did exactly the same thing recently, by hand, no disc cutter. I used a 1050mm lintel from Jewsons.

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knocking out wall

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