Do I need to put steel in the floor Slab? Passive can be expensive.

SRV

Hi again,

I will begin my build shortly and have a few details im not sure of....

there is no mortgage for this build.

im building a 100 mm block build, simple bungalow with 200 mm cavity. Its 200 msq.
Using a non conducting wall tie....not sure which are available these days?

I want to acheive a very high level of energy efficiency, without going to the level of passive as my budget is quite limited. I believe its not very difficult or expensive to acheive this cheaply, by being super careful with the detail.

Triple glazed 0.8 windows. All windows and doors and joints sealed for airtightness and MHRV used.


Is it necessary to use steel mesh in the floor slab? This is expensive and if it could be avoided i would prefer. Unfortunately this bungalow is not very compact as its 21 metres long. Long slab. Is the steel to stop cracks and therefore air leaks?


How do i lessen the cold bridge between the floor slab and the inner leaf of the wall? Should i be putting some insulation between the slab and the wall.? If so how much?

I will be allowing the full fill bead to go below the floor level in the cavity.

Is it worth it to use quinnlite blocks on the inner leaf from the foundation up to the floor level?



If i use insulation between the slab and the wall, how do i make the joint airtight?
Do I use a piece of membrane which would be sand/cement plastered to the wall...........and how would this be jointed to the slab?
Whats a clever/cheap detail for this area?


thank you very much

SRV

Viking House

If you have good ground and compact the stone under your slab in 2 inch layers with 6 passes per layer using a 100kg compactor you should have no settlement. Then you can use A193 (7mm) or A142 (6mm) mesh which is quite reasonably priced.

alexshinefagan

Hi,

I am a working Engineer and would recommend you to get some advise regarding putting steel in your floor. If your floor needs to carry any internal load bearing walls it will need a minium of A252 mesh, but you need to get professional advise, you need an engineeg to calculate the dead and live loads that will be imposed upon the final structure, otherwise your structure could fail. A142 mesh is only to prevent cracking and would be of no structural strenght.

best of luck

AckwelFoley

Ive built houses and i can say happily one thing, nothing ive ever built has ever had structural problems.. one simple reason, i NEVER EVER try to cut corners when putting in a foundation. Its the one part of the house you cant go back and change realistically.

Get the professional advise and stick to it. Get an engineer as the above poster recommended and put in the steel correctly. Foundations are expensive, a good one is not an awful lot more expensive than a bad one, difference is a bad one will ruin the build.

muffler

Extract from the charter

On construction related matters any specifying of structural components is prohibited. Any queries in this regard need to be dealt with by an architect/engineer privately.

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