ideas to reduce the thickness of a new external wall

[Paul205]

Dear All,

I am considering a small external extention to my property which will be a single story extention with toilet and separate shower room.

The new extention will have 3 new external walls. Please can anyone suggest ideas that will reduce the thickness of the 3 new walls. I understand I have to have external brick, cavity and then blockwork. Perhaps there ways of reducing the thickness of these walls?

Kind Regards




Paul

 

[garyo]

You don't have much wiggle room if you're building masonry : Take a look at page 6 of this LABC PDF foro some options :

http://www.derrycity.gov.uk/buildingcontrol/downloads/Herts U Values.pdf

Have you considered a timber frame extension?

 

[Porque223]

Use some material with a compressive strength per unit volume greater than the masonry.

 

[^woody^]

I understand I have to have external brick, cavity and then blockwork.

No you don't. The walls need to be weathertight, insulated and structurally sound

Just under 200mm is possible with a timber frame

 

[tony1851]

Presumably it's on the side of the house? You can get an extra 6" in width by taking out what is now the outer skin of the existing house wall and putting a beam in to support the wall above.
Timber frame would also give some additional space, but be careful if you are doing this under p.d; the materials should match those of the house to qualify.

 

[tony1851]

Use some material with a compressive strength per unit volume greater than the masonry.

Like what!?

 

[Porque223]

Use some material with a compressive strength per unit volume greater than the masonry.

Like what!?

Probably some composite that is too expensive to use for buildings unless you are Bill Gates. . .

 

[tony1851]

Use some material with a compressive strength per unit volume greater than the masonry.

Like what!?

Probably some composite that is too expensive to use for buildings unless you are Bill Gates. . .

With single-storey masonry structures, the compressive strength of the units and the masonry as a whole is never the issue.
It is the relatively low tensile strength under lateral (ie wind) load that is critical.

 

[^woody^]

compressive strength of the units ..... is never the issue.
It is the relatively low tensile strength under lateral (ie wind) load that is critical.

It's more critical for the walls to be able to hold up the roof.

 

[tony1851]

compressive strength of the units ..... is never the issue.
It is the relatively low tensile strength under lateral (ie wind) load that is critical.

It's more critical for the walls to be able to hold up the roof.

No; for narrow, single-storey extensions such as the OP's, the weight of the roof is very low - almost certainly lower than the weight of the wall itself.
In those circumstances, it's the ability of the wall to resist the lateral wind load which becomes critical.

As wind load induces tension in the joints, and as masonry is relatively poor in resisting tensile forces due to bending, care has to be taken to ensure that walls are adequately supported along each edge.

(

 

[^woody^]

LOL, wind loading for the OP's situation is negligible.

So negligible that it's not even a consideration, and I doubt that you even give a passing thought to BS 6399 or do any of it's calculations in any design work you do for single or double storey buildings

But you surely would design a wall to hold up the roof

 

[Porque223]

I stand corrected.

 

[tony1851]

LOL, wind loading for the OP's situation is negligible.

So negligible that it's not even a consideration, and I doubt that you even give a passing thought to BS 6399 or do any of it's calculations in any design work you do for single or double storey buildings

But you surely would design a wall to hold up the roof

Woody;

Wind load is not 'negligible' as you state, otherwise how come free-standing brick boundary walls are limited in height?

No, we wouldn't do calcs for wind loading on a small extension; but the effects of wind load are factored into the guidance in AD A, and the limiting dimensions given there are largely based on wind load.

Assuming the OP's extension is 8ft high internally, then by analogy you would not build a boundary wall that high in brick/block cavity.

 

[tony1851]

Paul; tried to reply to your PM but can't get through.