Strip Foundations for Conservatory I'm Confused?

[CrossWise]

Hi Guys,

Any clarification would be very much appreciated.

Having dug footings for a conservatory the soil being heavy with clay to a depth of 90cm and to a width of 60cm I am ready to order the concrete which I am going to specify to a depth of 25cm on which to build the dwarf wall.

Having been surfing the net I am now confused as to the need for steel reinforcement to be placed in the strip before concrete is poured, as I now understand some concretes come with fibre reinforcement (?), is this the case, is this instead of using the steel mesh reinforcement?

Additionally I have read that you should make a hardcore base with sand seed before pouring the concrete, is this necessary for a strip foundation? I can understand such with a concrete path however its given me cause for concern (sleepless nights)?

Any help much appreciated.

Cheers Steve

 

[^woody^]

Seems like you are confusing foundations with floor slabs

You don't need reinforcement in strip foundations, and foundations go straight on to the ground with no fill material first

 

[CrossWise]

Cheers mate,

I feel a lot better now. Im just getting paranoid about this whole job. I'll order the concrete and see how it goes.

Thanks once again.

Steve

P.S. I notice your from Birmingham, you were unlucky today against Man U. You played well. Im a Bolton fan by the way

 

[alittlerespect]

Clay is a problem material, it shrinks when it dry's out (lack of rain) and it expands when it gets wet (too much rain), the worst part is that it can take upwards of ten years for this movement to become noticeable, by which time its too late to do anything and you are left with the headache of what to do next!

Its very unlikely that a 25cm depth of foundation will cope the the movement and you would be far better off filling the trench with concrete to about 15cm below ground level, and then start the brickwork.

As mentioned by woody, there may be a bit of confusion here with your interpretation of foundations and floor slabs!

Regards

 

[CrossWise]

Thanks for your post.

I was a little shocked by what you had to say, thats a lot of concrete. I guess the up side is that it means Ive less blocks/bricks to lay.

Thanks once again, its better to know now and do the job right than finding out in 10years.

Cheers mate, take care

Regards Steve

 

[stuart45]

Trench fill foundations have been quite popular in recent years as the extra cost of the concrete is offset by the savings in blocks, labour and concrete fill of cavity. However if you had decided on this method to begin with the trenches could have been made much narrower as working room in the trench is not needed. This would have saved a lot of concrete as a min of 300mm foundation width is required for a 1 storey building in firm clay soil.
Some clay soils are worse than others, with the shrinkable clays causing the most problems.