Help with the best way to build a conservatory dwarf wall

[eyedee]

Hi,

Over the past few weeks I've been renovating the rear of my property before installing a self build conservatory. Jobs already finished escalated in number, took longer than expected to complete and turned out to be costly, so I'm hoping to save some time and money when it comes to building the dwarf walls of the edwardian conservatory.

I've never built a full wall before (only repaired a pre-existing one) and I'm unsure what materials I can use to safely and cheaply build both skins of the cavity dwarf wall. I've had a good look around the net, youtube and in books but all advice tends to lean toward brick external skin and breeze block internal skin. Thing is, I'd already decided to render the external wall to suit the look of my house (I don't need the visual look of bricks) and so I was wondering if I could use breeze blocks or similar to build both the skins? The wall will be filled with a cavity insulation that I've already purchased.

I hope I've got this right ... there appears to be three basic type of breeze/aerated blocks available for wall building: Low, Medium and Dense density concrete? I guess the low density blocks are fine for the internal skin, but are any of the three suitable for building a solid external skin?

Thanks for reading and for your help.

 

[noseall]

Irrespective of whether you build from brick or block on the external skin, you will still need to show bricks on the bit of masonry that is below d.p.c. and above ground level.

For rendered finishes i would recommend using a lightweight aggregate block such as 'hemelites' or 'fibolites' as these have a high keying surface. Other lightweight blocks such as the aerated variety i.e. celcon or tarmac topbloc are not best suited for rendering.

You could use a dense concrete 7n block (which you would normally use below ground) but they are heavy, not easy to lay (particularly when wet)and do wander a bit at height.

 

[eyedee]

Thanks for your input noseall. Can I ask what you mean by your first line? The wall will be rendered to the patio and none of the brick/block work will be visible. At present my house is made out of brick but is fully rendered to below ground (earth) level well below the d.p.c. Must the brickwork below the line of d.p.c. need to be engineering bricks and mustn't be concrete blocks then?

Thanks for the suggestion re. lightweight aggregate blocks. I'll pop to a builders merchant over the weekend and see what they stock.

Initially I was looking at the Wickes range of blocks ( http://www.wickes.co.uk/bricks-blocks+lintels/aerated-blocks/icat/bbblock/ ) to build the internal and external skins from - although I wasn't sure if the dense concrete blocks would be suitable for the external wall?

 

[limerockconstruction]

The aerated blocks and medium density blocks would be fine for internal and external skins respectivley.

You can lay dense blocks below DPC to avoid the brickwork if you please. You will just need a bell-cast in at DPC level and once render coat the plinths. and depending on your floor make sure you use lintels to bridge the airbircks should they be needed.

BTW - those prices look very high for blocks.

 

[onecog]

I intend to go down this road with my conservatory base.

http://www.youtube.com/watch?v=57ZwcjljBMQ

 

[tony1851]

breeze block internal skin.

Doubt you'll find many breeze blocks at the builders' merchants

 

[eyedee]

Thanks very much limerockconstruction, that's very helpful. I'll visit Travis P. and Jewsons and see what deal they can do me on blocks.

onecog, I did see that modular system and it looks good, but I've already bought most of the bits I need to construct the base using building materials so I think I'll carry on down that route.

tony1851, sorry, that's gone right over my head?!

 

[stuart45]

tony1851, sorry, that's gone right over my head?!

He probably means that a true breeze block made from coke breeze is unlikely to be found in any merchants nowadays.
People tend to refer to any block as a breeze block, even if it's concrete, AAC etc.