Garden wall foundations - Building Help

tntcoder · 22 Jul 2008 at 13:27

Hey,

Need some help planning the foundations of a fairly large garden wall, its 23meters long, 2 bricks thick. My plan is to have 40cm deep foundations (35cm concrete + 5cm hardcore base). It will be about 6 bricks tall, maybe more (will decide later).

Ive just used a laser thing to check the height difference at each end, and the right end of the wall is ~ 13.5cm lower ground than the left, so ive decided to use steps to account for this, by splitting the 23m into 3x7.6cm level steps, which im hoping is the correct thing to do?

This is my current plan:

The problem im having is i dont know how deep each steps need to be? In the diagram i have put the top of each step at the bottom of the previous one, but this is probably way to deep?

Can anyone give me some pointers on how deep the steps need to be to keep everything nice and level?

Thanks,

Jack

rogue66700 · 22 Jul 2008 at 13:47

TBH I don't think its worth the effort to step it for that difference in depth, and your footing is overkill for 6 courses.

The_blue · 22 Jul 2008 at 13:47

Brick + mortar x how many steps to = 13.5

Or just dig till level.

tntcoder · 22 Jul 2008 at 13:50

EDIT: I would rather stick with the steps, a single brick + mortar is 9cm deep and i have 2 steps?

Ace of Spades · 22 Jul 2008 at 13:55

If your stepping the foundations overlap them by the depth of the step.

200mm deep found would be adequate depending on the ground strata for a wall

tntcoder · 22 Jul 2008 at 14:00

Ace of Spades said:
If your stepping the foundations overlap them by the depth of the step.

200mm deep found would be adequate depending on the ground strata for a wall

Thanks, so how deep should the step be? Simply 9cm for 1 brick + mortar on each side?

rogue66700 · 22 Jul 2008 at 14:01

An 8inch footing will be enough for the size of the wall you need, so dig down so that your footing is a couple of inches lower than the ground.

Get some wooden stakes and knock the first oneinto the ground at the dept of your footing and knock another one in close enough together to put your level across 2 stakes.

Put a level across to make sure they are level and repeat along the trench, then just fill with concrete to the top of the stakes and it should all be level.

Ace of Spades · 22 Jul 2008 at 14:09

tntcoder said:
Thanks, so how deep should the step be? Simply 9cm for 1 brick + mortar on each side?

400mm (40cm) down and 400mm across.

As people have said previsouly it would be easier to build everything at same depth.

tntcoder · 22 Jul 2008 at 14:17

ok thanks a lot guys, I think im understanding correclty, this is my new plan:

This means the right hand step would be 40cm + 18cm = 58cm deep?

Will that work ok?

rogue66700 · 22 Jul 2008 at 14:39

If you really want to step it it might be easier to just put one step in as you dont have to start cutting bricks in half. But as stated above for a 580mm you could put a conservatory on it!

andy m w · 22 Jul 2008 at 19:24

Hi ok lets start from the beginning.brick depths vary modern bricks are 65mm deep plus 10mm bed equels 75mm if you are buying new bricks this will be the best option.You would be best with just one step in the middle of 150mm which is two course of brick plus bed joints just dig the lower end the extra 1.5cm .To keep the wall stable you should really dig down to the level of clay or else the wall could subside .You would be able then to put a 150mm thick concrete foundation straight on top of the clay.DO NOT BUILD ON TO TOP SOIL OR LOOSE GROUND even if you use hardcore.

andy m w · 22 Jul 2008 at 19:34

Sorry forgot to mention use 7newton blocks below ground level this will not be seen and will be quicker and cheaper than using bricks.