# Forum Home Renovation Brickwork  How long for mortar to set so supports can be removed?

## montiee

I had to knock out a row of bricks (3 of them) just above the woodheater to remove an old woodheater from a chimney enclosure. Now that I've finished restoring the woodheater I plan to put the bricks back. At first they will be supported with a bit of timber to prop them up and to stop them falling down while the mortar sets but my question is how long do I need to wait before I can remove the support and the bricks will just hang there. The other question I have is how long until the mortar sets so you can't easily knock it out even if you do bump it ..  
Cheers!
M

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## GeoffW1

Hi, 
I'm unsure on your situation. Normally you would not depend on brickwork to hang unsupported by anything underneath it. I know you can find bricks looking like that, but it is not normal practice. 
Have I misunderstood? Is it arched brickwork? That can be self supporting. 
Otherwise you really should build in a galvanised steel lintel bar under the bottom row of bricks.  http://ingal.com.au/IGBS/archbar.pdf 
Cheers

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## montiee

> Hi, 
> I'm unsure on your situation. Normally you would not depend on brickwork to hang unsupported by anything underneath it. I know you can find bricks looking like that, but it is not normal practice. 
> Otherwise you really should build in a galvanised steel lintel bar under the bottom row of bricks.

  Yeh I know. It looks like they put a lintel in but one row of bricks too high and then just stuck an extra row beneath it that just hang there. Normally if this was archway where people walked under I would be concerned but since these bricks are just sitting above the woodheater there isn't any safety issue and I'm not going to go through any hassle inserting a lintel. Infact it would probably be too tight a fit and I wouldn't be able to get the wood heater in there which probably explains why they did it that way.   

> Have I misunderstood? Is it arched brickwork? That can be self supporting.

  No you are pretty much on target but it isn't arched brickwork. It's just another flat row of bricks. 
Pictures below will paint a clearer picture...
Fireplace which needs row of bricks replaced..  
The restored woodheater that will be slotted in place.    
So can anyone tell me roughly how long I should wait before I remove the supports and the mortar is dry enough so the bricks don't fall down?

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## pawnhead

If there's a metal bar in there already, then I doubt that they'll ever stay there, or they'll come loose very easily. There's nothing for them to adhere to on top except metal, and mortar won't stick to metal. If it was all cement mortar, then they should hang there after a week, but the longer you leave it, the stronger it gets, up to about 21 days when it tapers off. It keeps getting stronger for decades though.
Minimum stripping time for suspended concrete (similar sort of thing, same cement used) is 14 > 21 days. 
You can get 'tongue' bars that go in above the bottom course and they have U shaped tongues that go down the perps to hold the course below. 
In your case I'd just brick on top of the heater after you install it. Or if you're putting more than one course in, then key in the lower course, and install bricktor in the bed, weaving it down the perps and back up again, and along the bed. This will stiffen it considerably. 
BTW, it looks like you've done a nice job on the heater. I've been reading your threads. :2thumbsup:

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## montiee

> In your case I'd just brick on top of the heater after you install it.

  Unfortunately the heater has a raised lip and there would be no way to get the bricks in on top with the heater fully inserted. No one is going to mess with the bricks anyway so I might just go ahead and do it tonight and leave it for a week or two and see how it goes. 
The "lintel" isn't your traditional flat metal bar. It's more like 2 pieces of reo rod so there will still be some brick inbetween these two reo rods for the mortar to stick too.   

> BTW, it looks like you've done a nice job on the heater. I've been reading your threads.

  Cheers. The work has been rather fun however I won't miss carting the heater in and out of the house onto the yard as well as unpacking/packing up all the crap at the end of each day :lol:. The @@@@@@ weather hasn't done me any favours :lol:.
A pro would of done better smoother welds but for my level of experience before starting which was zero I'm quite happy with it all. I turned what amounted to scrap metal into a fully functioning unit again.

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## pawnhead

Wet the bricks first. Not soaking so they're oozing water, just damp them a bit, and the mortar will adhere better. If you've got some bondcrete, or PVA glue, then apply a diluted coat on the damp bricks before you mortar, and make sure there's solid mud all the way through for best adhesion. Use a stick to push it in if you have to.

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## montiee

Well I put it on last night. Took the support out today (24hrs later) and it's holding. I put the support back in till tomorrow but at least I know it should hold as I replace the bottom row of bricks in a couple days time..

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## Terrian

> Well I put it on last night. Took the support out today (24hrs later) and it's holding. I put the support back in till tomorrow but at least I know it should hold as I replace the bottom row of bricks in a couple days time..

  personally I would have just chiseled out some of the motor from the sides and put in a flat lintel. 
good luck with it.

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## montiee

> personally I would have just chiseled out some of the motor from the sides and put in a flat lintel. 
> good luck with it.

  You missed the bit about clearance. Even without the lintel it's going to be extremely tight to slot the woodheater in.. A few of mm doesn't sound like much but I in the end it makes all the difference in the world.. 
Seems to be holding fine without supports now so fingers crossed..

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## Uncle Bob

I probably would've notched out the inside edge of the bricks and put a lintel in. 
The heater looks great. I used to have that same model in a shack on the farm. It too had a broken pane so I just pop riveted a piece of sheetmetal over where the glass was. Worked well, especially since I used to use it with the door open most the time.

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## montiee

> I
> The heater looks great. I used to have that same model in a shack on the farm.

  Any idea when it was manufactured in?. I know it's over 35 years old. Mine has the original label but all it says is manufacturer, the patent number and the serial number. Obviously before googles time as well.   

> I just pop riveted a piece of sheetmetal over where the glass was. Worked well, especially since I used to use it with the door open most the time.

  Well replacing the glass will set me back ~$90 but that is for one piece (entire window). The frame would cost me <$10 in raw steel (oriignal frame door is brass and not in great condition anyway) and probably 1-2hrs to knock up and install. I thought about doing it as part of the restoration before I plugged it back into the wall but figured I didn't want to waste money until I run it during this winter to see if I was happy with it in general wrt the heat output and mess of the wood.

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## Uncle Bob

> ObviouAny idea when it was manufactured in?. I know it's over 35 years old. Mine has the original label but all it says is manufacturer, the patent number and the serial

  No idea mate, I had this over twenty years ago and it was old then.

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## Terrian

> You missed the bit about clearance. Even without the lintel it's going to be extremely tight to slot the woodheater in.. A few of mm doesn't sound like much but I in the end it makes all the difference in the world..

  if the clearance is indeed that tight, I would have cut a slot into the bricks and slid the flat bar lintel into that  :Smilie:    

> Seems to be holding fine without supports now so fingers crossed..

  hopefully you are lucky and it all holds. good luck  :Smilie:

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## montiee

> hopefully you are lucky and it all holds. good luck

  It held for 35+ years before that so don't see why just one row of 3 bricks span and not even full length bricks at that (had to cut them down to size) won't sit in place for another 35+ years. They certainly not going anyway before I put a chisel and hammer to the mortage to dislodge them. We were so aggressive banging the heater against them to try to get it out and they wouldn't budge. Not sure I need to be lucky really based on past history. That's why I didn't feel the need to over-engineer it given it's already proven itself. Like I said if it was a door way I would of gone through the extra effort just to be sure but over a fireplace it's not that critical even if it does fail (highly unlikely). It's just a matter of letting the mortar set to max strenght before knocking it around.

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## GeoffW1

> It held for 35+ years before that so don't see why just one row of 3 bricks span and not even full length bricks at that (had to cut them down to size) won't sit in place for another 35+ years. They certainly not going anyway before I put a chisel and hammer to the mortage to dislodge them. We were so aggressive banging the heater against them to try to get it out and they wouldn't budge. Not sure I need to be lucky really based on past history. That's why I didn't feel the need to over-engineer it given it's already proven itself. Like I said if it was a door way I would of gone through the extra effort just to be sure but over a fireplace it's not that critical even if it does fail (highly unlikely). It's just a matter of letting the mortar set to max strenght before knocking it around.

  Hi, 
Look, I don't mean to be rude, but are you sure you even needed to ask? 
Cheers

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