Concrete footing/quantities advice

Starting a nice little project next weekend.
Its a dwarf wall greenhouse 2.5m x 4.3 (8x14feet).
It will sit on a single skin brick wall 500mm high.

For the footing i'm going to go 200mm wide and 150mm deep.
Is this enough ?,
I have a barrow full of old wall tiles+roof tiles to throw in the footing,
Do I need rebar?

I used an online calculator and it tells me I need just over .4m3 of concrete. C20 mix.

134kg of cement
250kg of sand
500kg of gravel

Does this sound right ?I dont want to order too much but I need extra sand and cement for the block work mortar.

Any other advice for me ?
Thanks

Calahonda52

What depth are you going down? eg frost heave
What is the ground like?
What width are the bricks?
200, ie 8 ", wide is too miserable, ie 6" is too thin: this is the real world, not adult lego

you wont get 0.4m3 delivered at a reasonable price

Calahonda52

Calahonda52 wrote: »

What depth are you going down? eg frost heave
What is the ground like?
What width are the bricks?
200, ie 8 ", wide is too miserable, ie 6" is too thin: this is the real world, not adult lego

you wont get 0.4m3 delivered at a reasonable price

solid ground.
Bricks are standard width red bricks 115mm or so.
Going to mix the concrete myself with a mixer.

What do recommend so ?

Edit-good site here for diyers like myself.
http://www.pavingexpert.com/featur03.htm

Looks like 300mm wide and 200mm deep is recommended ,

bfclancy

BrownFinger wrote: »

solid ground.
Bricks are standard width red bricks 115mm or so.
Going to mix the concrete myself with a mixer.

What do recommend so ?

Edit-good site here for diyers like myself.
http://www.pavingexpert.com/featur03.htm

Looks like 300mm wide and 200mm deep is recommended ,

Go with 300 by 200 be plenty for a single skin. Red bricks are crap for fixing to so try and use solid red bricks with frogs rather than holes or else go for a stock brick

Calahonda52

300 by 200, with top 150 minimum down with a bit of rebar will work.
Don't know about the single brick wall, 500 high with no piers.
I am building one later this summer and will use 4" solid concrete block on the flat: much more stable, very quick to lay and plenty to tie my glasshouse to

policarp

Depends on where you are.
Some areas only need a small cutting to meet the marl.
Others have to dig a bit deeper.
But the general rule of thumb is 3 times the wall size.
So if you have a 100 mm. wall, then foundations should be
300 mm.