Thread: New window in an existing brick wall...

G'day Dallas, its a job that if I had to do, I would be taking a great deal of care considering you have all that brickwork and weight above where you will be cutting the hole. I would always err on the side of caution and definitely prop/support.

I believe the coach of Port Power Football club lost a brother a while back, crushed by falling brickwork when removing a window frame! So take care.
Jack

Dallas,
I would approach this with extreme caution! You've got 3-4M of bricks above you and possibly a roof load as well. I've never cut holes in a brick wall before (plenty of timber and masonry block ones though) so I'm not speaking from experience here. Presumably you're going to fit some sort of lintel. It would make more sense to me to slot the mortar out with a grinder and diamond blade and slip the lintel in place before cutting the window out. Otherwise you're relying on the mortar to hold everything together for a day - that's a scary thought. :eek:

Mick

Guys,

Just had another builder around this morning, to quote on removing the piers under my house, and his thoughts on the window was to just punch a hole out and rely on the above brickwork for the temporary supports until I fitted the lintel...
but Mick, your suggestion is a cracker, and makes me feel alot more easy about the process, especially when I start at it with Mr Sledge...

Cheers


D

http://www.readersdigest.co.uk/diy/webpages/236.htm

this might give you some hints on making the initial hole in the brickwork.

I know that I've got instructions how to put a doorway in an existing brick wall somewhere at home ( mick's suggestion fits in with my memories of the article ) I will try and dig it out for you at the weekend.

This info is from Collins Australian Do-It-Yourself Manual. Might be of some use to you.

Disclaimer: I am not a pro,
But I've cut a few openings for ducted heating units. The last one was 4.5 bricks wide (slightly over 1m). I can tell you that in neither of those cases the bricks above the cut had any room to fall out. Mortar does not compress, so the only way a brick can fall if it is either slides out perfectly out of the course (impossible) or mortar on the side of it falls out. If you have a solid wall above it, and more importantly around it -- there is no way it is going to collapse inside the cut -- the weight of bricks on a side will keep them up. You need lintel only to support few bricks just above the cut, and only if the mortar is of poor quality, the bricks that are engaged into side wall above the cut are going to stay there. Just watch out for the control joints, as it will change things completetly.

I would also suggest using a combination of a demolition/rotary hammer and a large angle grinder. Even the cheap hammers that are in abundance in bunnings work very well, and you will avoid applying great forces to the wall in its weakest point -- sidewise. The trick is to remove the first brick -- drill few large holes and chip away.

When I was doing my renovation I hired a bricklayer to do the brick work. When he finished I took him to the old side of the house and asked him how much would he charge to cut a man hole to go under the house and I pointed at a lintel that was left over from the work we had done. I said I wanted it 3 bricks wide.
Whitout a word he took a mallet out of his truck and asked where do you want it?
Here I said.
And he started clubbering the wall, each hit was a brick that flew under the house. In a matter of 30 seconds there was an opening and 30 second more the hole was finished, square and stright. No lintel. And it remained without a lintel for the last 2 years with not one single solitary crack.

As a matter of interest and coincindence, here is the lintel I am placing above a door I am widening and making higher. I chipped away the existing render and then used a 9 inch angle grinder with a diamond tipped blade to cut along the mortar the length of the steel I was going to use for the lintel.

However I have since decided to use to lengths of hardwood as a lintel, as I will run some brickies mud above the lintel and under any gaps between the brickwork.

I also re-strutted a roof collar strut, which was sitting above the door space. Check your roof for struts holding up the roof collar (the collar is timber that circles the inside of your roof about halfway up), the struts stop the roof from sagging.

And for the eagle eyed check out the fantastic steel conduits used for the wiring of the house. Amazingly the house was rewired, but they used the existing steel conduits to run the wire down - how bizarre is that.

Cheers

PS I would never take the risk of assuming the mortar would hold the brickwork for any extended length of time, houses move.

We put some french doors in place of an old half height aluminium window, double brick load bearing wall. Have builder or structural engineer check structure above.

Got quick cut dry saw (Hire - chainsaw with concrete cutting saw blade) and cut bricks (one course only) from one side (makes hell of mess). Push steel lintel under side cut and prop with acro shores. Go around other side and cut other course of bricks, check ends into mortar at tops with saw and slide steel lintel into place. At no time remove shores. Cost $1,100.00 all up including tas oak door frame and cheapo french doors.

Cheers

Originally Posted by namtrak

And for the eagle eyed check out the fantastic steel conduits used for the wiring of the house. Amazingly the house was rewired, but they used the existing steel conduits to run the wire down - how bizarre is that.

I use to be a sparky in another time and another world... every wiring I have ever done, be it domestic or industrial was always done in steel conduit. In fact I find it bizarre that we don't have them here and that wires hang sort of loose everywhere going through makeshift holes in the framework making it impossible to replace an electric wire.

I agree with Mick. I wouldn't advise cutting the hole without knowing what the load is on that part of the wall.
I put a window in a brick wall 12 months ago and inquired about hiring a wet saw to cut the hole. It worked out cheaper by about $40 to buy a crappy Ozito 230mm angle grinder and 3 masonry disks. The wet saw would have done a quicker job but I've had a lot of use out of that grinder since.
Cut a slot in the wall where the top of the window will go and you can just slide the lintel into place. Then you can cut the opening at your leisure.
It also saves a lot of work if you just work out the window size by using the mortar lines and then get the window made to fit. That way the grinder only has to remove mortar at the top and bottom and you have to cut every second brick down the sides.

Originally Posted by Marc

I use to be a sparky in another time and another world... every wiring I have ever done, be it domestic or industrial was always done in steel conduit.

Really, but the way I see it with the ceiling covered, in the steel conduit all it needs is for a live wire to be touching the conduit somewhere, and if I then touch the conduit and maybe the fridge, air con etc then I'm getting zapped without a circuit breaker.

I agree with conduit, I just would have thought plastic would have been more reasonable?

From one of my DIY books ( this deals with making a hole between two rooms so take what information you feel is relevant )

you need a minimum of 4 pairs of props - one pair supports the joists in the ceiling above if they run at right angles to the wall ... this may be the case for you or it may not ... scaffold boards above and below - props should be 600mm from the wall and no more than 900 mm apart.

Obviously if you have a wall which is dividing two rooms you may need another pair of props supporting the joists on the other side of the wall.

Two pairs of props are used to hold the needles pushed through the wall above the lintle. If the opening is more than 900mm apart you will need a third pair of props and so on ....

The needles are sound knot-free structural grade timber 75mm or 100 mm square and should be long enought o give a clearnace of up to 600mm on either side of the wall.

About 150mm in from either end of the proposed opening draw lines vertically upwards using a straight edge. About 2 brick courses above the linlebeween the two lines mark positions for the lintles ( i.e. square holes ). Using chisel, bolster and lump hammer remove enough masonry to make holes big enough for the needles. remove all the mortar so that the needles will bear on masonry not on mortar.

slide the needles through the wall supporting both ends with props, the bottoms of the props should be on scaffold boards. Check that the props and the needles are level with the needles butted up against the bricks above. Nail the end plates of the props to the scaffold boards.

You can then chisel out a brick course for the lintel. Try to leave the mortar underneath the row of bricks above but remove the mortar below the bricks so that the lintel has a level seat to sit upon.

slide the lintel in and pack the gap ABOVE with stiff strong mortar, working from both sides of the wall. Before the mortar goes off lever it up and pack the gap underneath on both sides of the lintel with slates, check for level using more slates if necessary.

leave the lintel for two days before knocking down the wall.

There are lots of detailed pictures - these show the needles still in place until after the edges of the hole have been done. you then put bricks back in the hole where the needles were.

Jackie

PS I cross referenced against another book and it too recommended using needles and supporting any joists at right angles to the wall.

Re the electrical wiring in conduit: The electrician who did my rewiring utilised the old metal conduits which were already in place in the walls. He tied the new wiring to the old and pulled it through - saved cutting grooves in the wall and the necessity of replastering. Since the house only had a few powerpoints, this technique mainly applied to the light switches. We replaced the old brown Bakelite switches with new "old brown" plastic ones.