Query re laying concrete blocks?

Forestboy1978 · Thu Mar 09, 2017 6:32 pm

Hi guys,

Basically a wall fell down and I quoted to put a 6ft panel fence in its place.

They wanted 2 course concrete block base and panels on top. Concrete is to hold in soil.

So anyway I've started the job and put in most of the posts without the panels so I can lay the courses tomorrow and let them go off before slotting in the panels.

Issue is this.. the concrete foundation was terrible. Great for me cos I anticpated 3 hours a hole and it's only been 1 hour per hole but crap for the new blocks. The foundation is stepped on the hills as you'd expect but it's not level.

I was thinking of either of these things

1- Make a bedding of 3:1 mortar and make it as thick as needed to keep the bottom course level

or 2 - Cut blocks and the right angles to accomodate the unlevel foundation.

I think I prefer option 2 as I don't want to be having to make 2 difference mortar mixes simultaneously. I.e 3:1 for bedding the bottom course and 4:1 for every where else. Might get tricky.

Also in area where the foundation doesn't step down in line with my panels I have the odd 8 inch step down to the next part of wall foundation that I need to make levels up. Same question really. Cut a block or fill with mortar? It's only 2 courses so it's not a house or anything but it still needs to be strong.

Ta guys

rxbren · Post: # 112650Post **rxbren** Thu Mar 09, 2017 6:49 pm

Would have been better off using concrete posts and concrete gravel boards instead of the 2 courses of block
Thick layer of mortar not ideal
If the concrete foundation is terrible what's to stop it being the cause of your block wall failing

Forestboy1978 · Thu Mar 09, 2017 8:00 pm

Concrete gravel boards aren't strong enough for this. It's clay. It'll pop them no trouble whatsoever.

Well, that's my issue re the concrete foundation. I do think it has settled to it's final destination now though but yeah. I mean the wall was there for 30 years before it fell apart also. I'm just wondering what's best to get the area level for the bottom course.

I'll put some photos up tomorrow but by then I'll have started laying the blocks.

jwill · Post: # 112652Post **jwill** Thu Mar 09, 2017 8:27 pm

Blocks on flat or 2 course high 4" thick?

Forestboy1978 · Thu Mar 09, 2017 8:52 pm

jwill wrote:Blocks on flat or 2 course high 4" thick?

They're not going flat.

8.5 inch height 4 inch depth 16 inch length.

Post: # 112655Post **seanandruby** Thu Mar 09, 2017 9:28 pm

You can't be serious about a thick bed? Maybe you could scabble and level the base with grano, or drill rebar in lacers and place a shutter then concrete a mini wall. Or as you say: cut blocks to suit, or break out and start again.

Forestboy1978 · Thu Mar 09, 2017 9:46 pm

seanandruby wrote:You can't be serious about a thick bed? Maybe you could scabble and level the base with grano, or drill rebar in lacers and place a shutter then concrete a mini wall. Or as you say: cut blocks to suit.

I was serious. We are talking about creating a bed that increases from about 1 cm to about 3 inches over the span of 2 meters to hold 2 courses concrete blocks. I mean 3:1 would be almost or as strong as the concrete blocks themselves surely so what would be the harm.

Or maybe just laying a dry concrete bed underneath the areas where the foundation has sunk. Laying the first course with a bit of SBR to aid stick. Let it go off for a bit and come back and lay the second course as normal?

lemoncurd1702 · Fri Mar 10, 2017 6:55 am

If the foundation has sunk then the foundation is F****d. Stop twatting about and lay a new one, by the time you fart around trying to level the existing one which sounds unsuitable, you'd have had it done anyway.

Forestboy1978 · Fri Mar 10, 2017 7:53 am

Sure cos I factored in excavating and re laying a concrete foundation into my fence quote.....

Post: # 112661Post **seanandruby** Fri Mar 10, 2017 8:04 am

Don't think you'll get amyone advising you on a thick mortar bed, it's not the done thing, 10 ml, 15 ml tops, bedding joint etc: yours will be a major bodge and this site is called paving expert after all :;):

Forestboy1978 · Fri Mar 10, 2017 6:08 pm

OK, no thick mortar bed. Got it!

Haven't got round to doing the blocks yet but have all posts in. Bear in mind the courses will be broken with the posts and then the ends of each course will be mortared into the groove in the post for slotting the panels in.

So what I've decided to do is lay a flat concrete bed to lay the blocks onto. It is only 3 panels that need this as the rest of the foundations are level. I'll have to cut and break out some conrete at the high pount to allow me to get a suitable depth of concrete to shutter in.

Any issues with this I'm all ears?

Forestboy1978 · Fri Mar 10, 2017 6:09 pm

lemoncurd1702 wrote:If the foundation has sunk then the foundation is F****d. Stop twatting about and lay a new one, by the time you fart around trying to level the existing one which sounds unsuitable, you'd have had it done anyway.

Sorry mate. Was in a massive piss this morning when I replied.

Ta for input.

jwill · Post: # 112675Post **jwill** Fri Mar 10, 2017 9:00 pm

So is a 4" block wall with mortared perps stronger than a conc gravel board with regards to retaining?

Post: # 112676Post **seanandruby** Fri Mar 10, 2017 9:40 pm

... Maybe the client wants it.

lemoncurd1702 · Fri Mar 10, 2017 9:46 pm

Forestboy1978 wrote:
lemoncurd1702 wrote:If the foundation has sunk then the foundation is F****d. Stop twatting about and lay a new one, by the time you fart around trying to level the existing one which sounds unsuitable, you'd have had it done anyway.

Sorry mate. Was in a massive piss this morning when I replied.

Ta for input.

No worries, I know what it's like, we've all been there.