Could you run your eyes over this please gentlfolk.

[twm.bwen]

Hi guys, I'm going to be building a porch that will be a glazed wooden frame, with clay tile roof over single skin sandstone dwarf wall.
I'm about to dig the footings so I was wondering if you pro's could run your eye over my method.

Easier to draw than exlpain

Have I got anything correct in there?
Thanks for the comments

 

[AndyBill]

cant see it !

 

[^woody^]

Is it a new postage stamp? Wheres the Queens head?

 

[Richard C]

Tried saving & magnifying it still can't see it; definition is not high enough, all blurred.

 

[twm.bwen]

Oops

Try this

Any better/

 

[twm.bwen]

Arrrrrr! Thar she Be!

 

[Bowness72]

It looks like you have the 9 x 9 blocks poking out of the ground a bit.

 

[twm.bwen]

I could change the top 9x9 to a 9x4 the reason behind it being above the ground level is that I want to keep the sandstone above the dpc.
But having thought about it, considering its a single wall then I guess it makes little difference wether there's a dpc or not!
Correct?

 

[noseall]

if you are building a porch then definitely use dpc.

 

[masona]

Won't the driving rain hitting the mortar joint at 4" thickness wall giving you damp problem, it's not a cavity or solid wall.

 

[twm.bwen]

It can only be singe skin due to trying to fit most area inside with a set external size.

Arn't some old houses single skin? How do they stop moisture through mortar joint? What about water proof additive in both bedding for bricks and internal render.

Also I doubt /hope there will be not too much penetrating damp as the proch will not be heated in anyway and i will retain existing external door thus reducing any temperature and humidity gradients.

But in terms of the contsruction (footing depth thickness, slab, insulation etc) does it llok about right?

 

[denso13]

Foundation should be at least 450mm wide to give scarcement on concrete.

Arn't some old houses single skin

Yes they are but around these parts tenaments can be 600mm thick as driving rain can penetrate 550mm into the wall.

Cavity walls provide protection as moisture which travels through the brickwork, and it does, gets stopped at the cavity and runs down the inside face of the outside wall.

 

[^woody^]

I can't see the point of insulating a floor in a porch with 4" walls, a small floor area and mainly glass.

The sand blinding can be 25mm

You don't need 9" blocks below ground - keep the wall 4"

DPC should be 150mm above ground level

You need at least 6" but preferably 9" frost cover below ground - so use engineers. And I would mass fill with contrete to 225mm below ground