how much mortar do i need?

[AstonHill]

Just to check here

Are you serious?

i take it that you have never made concrete walls before then!

 

[JohnD]

For the work you have in mind, the cost and effort of single-use shuttering will be considerable. With vertical pour, the pressure at the base of the column will be proportional to the height of wet concrete above.

I think you are trying to have a bit of fun with us, suggesting a crackpot scheme.

 

[robinbanks]

I just messured the windows and times by 3 and added them up
But its the inside frames of one large window, 2 medium and one small

Not an algorithm that makes sense to me I'm afraid. Measurements in centimetres for all apertures please; depth, width and height

I though pouring cement into them sanwitched by a board would be easyest and cheapest as not sure if room for blocks

Any hole of any size can be bricked up. Price breakdown later

is that not wet with the weight of water

Not really. Per my post the weight of the water, it is about the same as the weight of the cement or 300kg. Most of that doesn't "dry out" because it ends up locked in the crystal lattice that is the result of cured concrete. To most intents and purposes you can consider the weight of cured concrete vs uncured as the same. I avoid use of the word "dry" because it's not accurate; hardened concrete has cured, not dried. Concrete will set underwater

more then likely slightly less then a square meter and about 13-18cm thick

Just give the exact measurements please; four 90x90x15 cm windows would be just under half what you've calculated which would mean a lot of wastage

i take it that you have never made concrete walls before then!

John's pointing out that the usual method is to use bricks or blocks. Doing it in concrete needn't be onerous or particularly more expensive though.
Doing it in concrete commons, if your cubic metre is accurate, would take around 320 bricks at 40p each (concrete commons) and 300kg of mortar (420kg half sand bag £30, 2 bags of cement at £5 ea) so £170
Doing it in 140 concrete block, would take around 40 blocks at £2.20 each, plus 100kg of mortar (£3 per bag x 5, plus 1 £5 cement) so £100
In ready mix concrete at £170 a cube
In self mix it's 2 bags of ballast at £40 a pop, 12 bags of cement and a lot of hand shovelling if you don't own a mixer for your £140

Don't forget you'll need some shuttering ply if you don't have any already. You'd need one 8x4 sheet per window if using readymix or one sheet for the job if self mixing

 

[Mottie]

Why not use paving stones set on edge - you can get them for free under the cover of darkness but don’t take the ones outside the squat…..

Just a thought, are building control/planning involved?

 

[AstonHill]

Not an algorithm that makes sense to me I'm afraid. Measurements in centimetres for all apertures please; depth, width and height


Any hole of any size can be bricked up. Price breakdown later

Not really. Per my post the weight of the water, it is about the same as the weight of the cement or 300kg. Most of that doesn't "dry out" because it ends up locked in the crystal lattice that is the result of cured concrete. To most intents and purposes you can consider the weight of cured concrete vs uncured as the same. I avoid use of the word "dry" because it's not accurate; hardened concrete has cured, not dried. Concrete will set underwater

Just give the exact measurements please; four 90x90x15 cm windows would be just under half what you've calculated which would mean a lot of wastage


John's pointing out that the usual method is to use bricks or blocks. Doing it in concrete needn't be onerous or particularly more expensive though.
Doing it in concrete commons, if your cubic metre is accurate, would take around 320 bricks at 40p each (concrete commons) and 300kg of mortar (420kg half sand bag £30, 2 bags of cement at £5 ea) so £170
Doing it in 140 concrete block, would take around 40 blocks at £2.20 each, plus 100kg of mortar (£3 per bag x 5, plus 1 £5 cement) so £100
In ready mix concrete at £170 a cube
In self mix it's 2 bags of ballast at £40 a pop, 12 bags of cement and a lot of hand shovelling if you don't own a mixer for your £140

Don't forget you'll need some shuttering ply if you don't have any already. You'd need one 8x4 sheet per window if using readymix or one sheet for the job if self mixing

Hear are the messurements of the windows in cm by length, height and width, please not that the width is not that acurate due to the fact that half the glass is presnet and the other half is boarded up with wood
150x165x18
167x87x17
88x165x15
84x82x17

I though pouring cement would be the easy option given the fact that the bricks may not fit and i have never layed bricks before

 

[Mottie]

Why are the other halves of the windows boarded up with wood? Did the front door have a padlocked security cage over it when you 'moved in'.

 

[robinbanks]

Well given that all those dimensions are a bit more than a 140mm concrete block I really would be tempted to use them (blocks) as a single skin will fill the hole nicely and still leave about 15mm depression in the wall either side for it to be rendered flat concomitant with the surrounding edges

Don't worry about laying blocks, it's only marginally more difficult than LEGO. They're easy to build with because they're always an accurate size and square. You could find some board (ply, osb even furniture panel) 15 to 18mm thick, fit two timber spars to it to make a really fat H shape then screw it to one side of the wall so it fills the gap, use it to guide your block laying (push the blocks against it then lower them onto the mortar bed) and it'll make your wall flat and as vertical as the surrounding wall. The hardest part of the job will be mixing the mortar; newbies always put too much water in but the trick is to stop adding water when it looks like apple crumble topping in the mixer, and just leave it to turn and let the plasticiser foam up and make the mortar a nice consistent fluffy, like angel delight. Too much water and it's like sand soup and it doesn't need much to turn it from nice to awful. Dont mix a big batch for your first few goes cos you'll be pratting around with it more than you should. Remember it's getting rendered after (maybe) so doesn't need to be the neatest job


Before you begin though, I have to ask; is this a solid wall? Does it need to have any insulation (is it enclosing a habitable room)?

That may change the approach, and in some senses make it easier
-

Ok, those dims are pretty much the cubic metre already calc'd so I'll stand by the prices I've worked out

 

[Notch7]

as not sure if room for blocks

I don’t understand why.

As long as the window opening is deeper than 100mm, blocks will fit.

 

[bsr]

The blocks will also need tieing into the adjacent walls. Bang some 100mm nails into the mortar at each joint.

 

[foxhole]

Just to check here

Are you serious?

I think he’s converting a porta cabin.

 

[AstonHill]

Well given that all those dimensions are a bit more than a 140mm concrete block I really would be tempted to use them (blocks) as a single skin will fill the hole nicely and still leave about 15mm depression in the wall either side for it to be rendered flat concomitant with the surrounding edges

Don't worry about laying blocks, it's only marginally more difficult than LEGO. They're easy to build with because they're always an accurate size and square. You could find some board (ply, osb even furniture panel) 15 to 18mm thick, fit two timber spars to it to make a really fat H shape then screw it to one side of the wall so it fills the gap, use it to guide your block laying (push the blocks against it then lower them onto the mortar bed) and it'll make your wall flat and as vertical as the surrounding wall. The hardest part of the job will be mixing the mortar; newbies always put too much water in but the trick is to stop adding water when it looks like apple crumble topping in the mixer, and just leave it to turn and let the plasticiser foam up and make the mortar a nice consistent fluffy, like angel delight. Too much water and it's like sand soup and it doesn't need much to turn it from nice to awful. Dont mix a big batch for your first few goes cos you'll be pratting around with it more than you should. Remember it's getting rendered after (maybe) so doesn't need to be the neatest job


Before you begin though, I have to ask; is this a solid wall? Does it need to have any insulation (is it enclosing a habitable room)?

That may change the approach, and in some senses make it easier
-

Ok, those dims are pretty much the cubic metre already calc'd so I'll stand by the prices I've worked out

So if we where to go on the notion of blocks and filling the gap with cement then how many blocks do you think i will need?
and how much cement sand and hard cord do i needs as well?
Is the mix the same for the filler as the blocks

I presume it is a solid wall and yes it is an enclosed habitable room (though i though the cement filling/ blocks would insulate enough)

Thanks

 

[AstonHill]

I don’t understand why.

As long as the window opening is deeper than 100mm, blocks will fit.

the windows dont open! and not supposed to be. it is to cover the gap between the window and in interior window frame

 

[Mottie]