Blockwork for windows and lintel

acurachris · 12 Jan 2019

Hi

I am doing the block work on my extension and I'm wondering the best way to continue around the ground floor windows.

I can run a full course of 75mm blocks on top of my wall now which leaves me at the correct height for the window and then the coursing is also correct for the lintel, or I carry on with the block work, insert 75mm under just the window and 75mm under the lintels. Hopefully the my pic will show you what i mean.

I'm thinking option "A" would be best although this means running a 75mm course all the way around the extension, can i cut my Celcon blocks to 75mm for this? They are lightweight blocks by the way.

Not to scale

Cheers for any input.

Bonni · 12 Jan 2019

The top picture means your coursing is out so it doesn't work for your cavity boards to wall ties.

Assuming a 6" (150mm lintel), then run 65mm cuts over it to keep the coursing. Bear the lintels 150mm minimum both sides.

Just close the cavities off with plastic Cavity closers.

https://www.toolstation.com/ybs-24m...feed&msclkid=d8cf3071459c1a1777236c4b686c4114

noseall · 12 Jan 2019

Bottom image. We (me) go to the trouble of cutting the shaped blocks that go beyond the window jamb.
[GALLERY=media, 102419]Shaped1 by noseall posted 12 Jan 2019 at 6:51 PM[/GALLERY]
[GALLERY=media, 102418]Shaped2 by noseall posted 12 Jan 2019 at 6:51 PM[/GALLERY]

acurachris · 12 Jan 2019

Cheers for your reply.

Bonni said:
The top picture means your coursing is out so it doesn't work for your cavity boards to wall ties

That's a good point, I didn't think of that!

Bonni said:
Assuming a 6" (150mm lintel)

I think it'll be 150mm although not got them spec'd yet.

noseall said:
We (me) go to the trouble of cutting the shaped blocks that go beyond the window jamb

I have a cutting saw, so could do this. They are lightweight (look at them and they snap!) blocks, do you reckon cutting them into an L would weaken them anymore?

noseall · 12 Jan 2019

And yes, I'm a cruel gaffer who makes the lads fill even the backs of the blocks too.

^woody^ · 12 Jan 2019

noseall said:
Bottom image. We (me) go to the trouble of cutting the shaped blocks that go beyond the window jamb.
[GALLERY=media, 102419]Shaped1 by noseall posted 12 Jan 2019 at 6:51 PM[/GALLERY]
[GALLERY=media, 102418]Shaped2 by noseall posted 12 Jan 2019 at 6:51 PM[/GALLERY]

Al'right smudger

noseall · 12 Jan 2019

acurachris said:
you reckon cutting them into an L would weaken them anymore?

They can't be any weaker than a block that has been deliberately cut. I do agree that for what strength you get from the more slender angled cuts, you may as well not bother. But for those with a bit of meat left - worth the effort methinks.

noseall · 12 Jan 2019

^woody^ said:
Al'right smudger

That is the back of the external course Woods.

^woody^ · 12 Jan 2019

With new blockwork, you always follow a 225mm gauge for the block wall, and deal with openings by having cuts below, and cuts for the bearings of lintels or beams as necessary to get them to the required height, and then if necessary cuts above the lintel to get back to the 225mm gauge of the adjacent blockwork.

noseall · 12 Jan 2019

The 'face' is pointed even though its being rendered....
[GALLERY=media, 102420]20181107_143453 by noseall posted 12 Jan 2019 at 7:13 PM[/GALLERY]

acurachris · 12 Jan 2019

^woody^ said:
With new blockwork, you always follow a 225mm gauge for the block wall, and deal with openings by having cuts below, and cuts for the bearings of lintels or beams as necessary to get them to the required height, and then if necessary cuts above the lintel to get back to the 225mm gauge of the adjacent blockwork.

Cheers, makes sense!