Porch: Timber, Solid Masonry or Cavity Masonry Dwarf Wall?

[purplechap]

I am soon to build a small rear porch (less than 3sqm and hidden behind my 2.9m boundary wall).

I only need to erect an 'L shaped wall' as it abuts an existing extension and will be built level with it.

I will obviously have to prepare a foundation (probably trench fill).

I have never built an external house wall (just garden walls) and I am not sure if I have to use a cavity for an external wall or not. I am pretty happy with the joinery required to build the door, window and roof lights, but the wall is something new to me.

As most of the L shaped "wall" will in fact be the door and window frames, and the longest section of dwarf wall would be less than 1.5m, I was wondering about "getting away" with a solid dwarf wall. What would I gain by doing a cavity wall here - much?

Given that I would have proper foundations, can I just build timber framing all the way to the ground level without any brickwork at all? I presume so. Where does the DPC go in this case, as the wood would be at ground level? (Which is probably why I need a wall of some sort right!?)

Thanks

 

[legs-akimbo]

Timber down to earth will be problamatic for obvious reasons.
To build a cavity wall would be easier than a solid construction unless you are using 12" solid block, as the courses would allow for a little discrepancy and still look good, plus the u-value would be improved. Lastly fill the cavity with a lean semi dry mix of concrete to six inches below the d.p.c. A blue brick d.p.c. is a nice feature, above d.p.c. just regular stretcher bond with insulation batts.

 

[purplechap]

Thanks legs.

The porch is against a stone built house and I intend to face the dwarf wall with stone so that it blends in better (I am looking for an excuse for a mini stone wall facing/building project as it appeals to me - and I have some stone knocking around). If not then I will render the wall and paint it in line with the early '40s extension.

This is why I was trying to "get away" with a solid wall, as a cavity plus stone facing would take the external floor area of the porch just over 3sqm which I was trying to avoid (I understand I can avoid planning permission this way).

So given the above, would a solid wall for this single story small porch be okay in standard 12" concrete blocks, given that it would be load bearing (windows and roof)?

 

[TexMex]

I intend to face the dwarf wall with stone so that it blends in better

Why not build with stone in the first place? You can still build a cavity wall with a stone outer leaf and brick (or block) inner.

reminds me of a joke I once heard.

Q How do you kill a Blue Elephant
A With a Blue Elephant shotgun

Q How do you kill a Red Elephant
A Wring it's neck until it's Blue and then shoot it with a Blue Elephant shotgun.

 

[purplechap]

Well it is a thought Mr TexMex. Though do I really want the first ever stone wall I build to be part of a load bearing wall... methinks not

However I'll muse on it as I dig the foundation trench. Cheers.

PS Your joke made me hoot (or was that an owl?).