[about2build]

Hi guys I've met with a couple of block layers in lieu of starting building in months time....Two options have been presented in relation to the detailing around the windows
1 Use 3 inch L blocks returned toward outer leaf
2 Cut block and turn in toward outer leaf and place some insulation board (1-2 inchs) between outer leaf and this block piece.

The cvavity is 150 mm

The L blocks are expensive as well 1 euro a block which will add up

Thoughts?

[BryanF]

Originally Posted by about2build

Hi guys I've met with a couple of block layers in lieu of starting building in months time....Two options have been presented in relation to the detailing around the windows
1 Use 3 inch L blocks returned toward outer leaf
2 Cut block and turn in toward outer leaf and place some insulation board (1-2 inchs) between outer leaf and this block piece.

The cvavity is 150 mm

The L blocks are expensive as well 1 euro a block which will add up

Thoughts?

were these the only options offered?

[about2build]

Ya Bryan, I'm worried about cold bridging as well, what you think?

[BryanF]

ye PM sent

[sydthebeat]

dont cut the blocks, fill the 150 at opes with rigid insulation.
windows etc are fixed by brackets on inner leaf.

[fclauson]

Suggest you get someone to detail out Ope prior to laying a single block

windows in low energy demand build offer the biggest headache for getting right - and the biggest thermal bridge if you get it wrong

will pm you a name

[esox28]

Originally Posted by fclauson

Suggest you get someone to detail out Ope prior to laying a single block

windows in low energy demand build offer the biggest headache for getting right - and the biggest thermal bridge if you get it wrong

will pm you a name

can you pm me please

thank you

[fclauson]

PM sent

[about2build]

Thanks guys, syd can you elaborate a bit....what fixes the rigid insulation in place to close the cavity?

[Mellor]

Originally Posted by about2build

Thanks guys, syd can you elaborate a bit....what fixes the rigid insulation in place to close the cavity?

THe fact that it has nowhere else to go.

[gears]

Originally Posted by fclauson

Suggest you get someone to detail out Ope prior to laying a single block

windows in low energy demand build offer the biggest headache for getting right - and the biggest thermal bridge if you get it wrong

will pm you a name

Any chance of that PM aswell, thanks.

[sydthebeat]

Originally Posted by about2build

Thanks guys, syd can you elaborate a bit....what fixes the rigid insulation in place to close the cavity?

its friction fitted between the DPC and the inner leaf.

The fitting of the window frame then abuts it and allows for cavity pumping.

[fclauson]

Originally Posted by gears

Any chance of that PM aswell, thanks.

PM sent

[braftery]

In order to really deal with the openings properly you need to consider the full wall build up .. including internal and external finishes.

For Example:

The use of stone on a building exterior. I have seen 4 different block laying solutions used in different parts of the country .. each with their pros and cons.

Traditionally people have considered making the building water tight as the primary objective and they have compromised all other issues to satisfy this one.

The stonemason job is to make the stone look well and stay on, the block layers job is to put the blocks up true, level and plum.

Do you think they are the best people to solve your buildings cold bridging issues ?

I suggest you sketch a section of the wall as it will look in the finished building ... work out the water tightness, air tightness and cold bridging issues on paper for the full envelope and then give instructions to the block layers.

Or hire someone to give you advice and draw these details for you.

Buying great components is not enough to build a great house .. you need to know how to put them all together too.

[scuggels]

What about the use of a cavity closer made by xtratherm suits cavity of 150mm? no need for cutting blocks etc