Concrete Block Garden Wall - guidance on layout

[unclebob1]

Hi All,

I am looking to have a 28m block wall built in place of fences (some of which are now neatly stacked up).

I'm trying to understand the block layout, number of pillars and expansion joints that various people have told me I need!

So the wall will be 2m high, 28m long, and stepping downwards. I want to plan out the foundations such that I dont need to mess about with filling in gaps at the base to get the block lines level further up - rather drop the foundation by a block height where the wall height will drop.

Should I look to put a pillar every 3m roughly? (each block is 440mm + 10mm mortar makes it 7 blocks at 3.14m or 6 blocks at 2.69m)

If the wall needs expansion joints, how far should these be, and how to place these in terms of the pillars?


Any diagrams or calculators for pillars/expansions would be useful to help me calculate!

Also from videos I can find, pillars are built using 2 blocks on their side for one row, and 1 block upright for the next. I'm planning on using 140mm blocks so this wouldn't work - can I use 100mm blocks on the flats, and 140 on the uprights? Or am I barking up the wrong tree?

 

[PaulJR]

Blockwork expansion joints are every 6m max, I would suggest you place them at the side of your pillars. If you use a channel system for the ties you can then step the wall at these locations irrespective of the coursing.

 

[unclebob1]

Thanks, so if do:
Pillar|2.25m block| Pilar| 2.25m block | expansion|Pillar|2.25m block| Pilar| 2.25m block | expansion|Pillar|2.25m block| Pilar| 2.25m block | expansion and so on?
Where the blocks on the left of the expansion are then not tied to the pillar on the right of the expansion or are you saying to not have the wall tied at all in brick work, and just use wall ties between the pillar and walls?

Pillar to pillar distance would be 2.7m, Pillar to expansion would be 5.45, 5 blocks in between each pillar..

Or if i go 6 blocks between pillars, it works out:
Pillar, 2.71 blocks| pillar| 2.71 blocks| expansion| pillar
Pillar to pillar would be 3.15m, pillar to expansion would be 6.35m and, 6 blocks in between each pillar.

 

[SFK]

Are you putting rebar into the pillars?

Asking as I did as locally some try to push pillars over on way home from pub.

I put in foundations, and then used SDS to drill foot deep hole into foundations, put in rebar this hole and built pillar or round it. Not strongest but does re-enforce pillar.
Sfk

 

[PaulJR]

Thanks, so if do:
Pillar|2.25m block| Pilar| 2.25m block | expansion|Pillar|2.25m block| Pilar| 2.25m block | expansion|Pillar|2.25m block| Pilar| 2.25m block | expansion and so on?

Pillar to pillar distance would be 2.7m, Pillar to expansion would be 5.45, 5 blocks in between each pillar..

I would go shorter - at 28m you will need 6 pillars at either spacing.

The pillars can be built up in any bond you like really, the expansion joints need a brick tie to bridge them - the tie will be "debonded" on one side to allow the joint to move as the blockwork expands/contracts, but will stop the wall from simply falling over. These are Halfen's products - which are a bit OTT for a garden wall but you can show it to the person behind the counter at a builders merchant and he can sort you out.

https://www.ancon.co.uk/products/wall-ties-restraint-fixings/other-restraint-fixings/movement-ties

 

[unclebob1]

Thanks @PaulJR
So if i go with 6 pillars total, 9 blocks between pillars, and have expansion on each pillar on both sides? or tie one side solid and let the other side expand?

So I would have:

Pillar|9 blocks + mortar| expansion| pillar| 9 blocks + mortar| expansion| pillar| 9 blocks + mortar| expansion and so on
Where the pillar would be 0.44m, and the 9 blocks + mortar would be 4.06m

Or expansion on both sides
Pillar| expansion |9 blocks + mortar| expansion| pillar| expansion| 9 blocks + mortar| expansion| pillar| expansion| 9 blocks + mortar| expansion and so on
Where the pillar would be 0.44m, and the 9 blocks + mortar would be 4.06m

 

[unclebob1]

Are you putting rebar into the pillars?

Asking as I did as locally some try to push pillars over on way home from pub.

I put in foundations, and then used SDS to drill foot deep hole into foundations, put in rebar this hole and built pillar or round it. Not strongest but does re-enforce pillar.
Sfk

No plans for rebar/re-enforcement, the wall will be behind a gate so not expecting many people of that nature to give it a go. Most likely damage would be from a vehicle who has mis-directed their aim, in which case i'd guess i would want the wall to fall away in that section rather then leave a solid lump for the car to hit?

 

[unclebob1]

Also, I was looking to build the pillars using the method in this video:

But that wont work as the blocks I am looking to use will be 140 wide, not 100 wide (so two blocks on the side will end up 300 not 200!)
Block size I am looking to use are:
440x215x140

What other methods would work for the pillar? Would I just do stacks of two blocks one way, and two blocks the other way? Then have NO blocks stitched into the wall, and just use the wall ties?
Or stitch it in to one side and use half blocks to make up the gaps?

 

[PaulJR]

Thanks @PaulJR
So if i go with 6 pillars total, 9 blocks between pillars, and have expansion on each pillar on both sides? or tie one side solid and let the other side expand?

Expansion at every other Pillar I think. I was thinking 6m crs as per the joints but you need them at ~3 m crs so Start with a Pillar/wall/Pillar/wall. Joint. Pillar/Wall/Pillar./wall Joint, repeat, last bay will be Pillar/wall/pillar/wall/Pillar, slightly longer to get your 28m.

Panels (I think) 1No. 5864mm [2 pillars](12mm exp joint) 3No. 5312 [2 pillars](12mm exp joints) 1No 5862 [3 pillars] total length 28010mm - with 12mm vertical (perp) joints insterad of 10mm.

not sure if you can read this image - long "Teams" meeting this morning

Regards the piers - it might be simpler to stack bond the blocks and just use wall ties in the joints, as long as they are tied to the wall - there are some hilarious videos on you tube of piers that are completely detached from the wall they are holding up.

 

[unclebob1]

What software did you use to create that image?
Looks like your suggesting 11 pillars an 5 blocks between with one end being 6 blocks?

 

[PaulJR]

I knocked it up in a package called ProStructures. I design steel signalling structures for the Rail industry as a living.
Yes it has 11, if it ties to the house or similar at an end, that pier can be left off.

 

[PaulJR]

If you want to model stuff, use google sketchup.

 

[unclebob1]

sketchup drawing... does it work? (Noth sure if the pillars are thick enough two blocks of 140mm?


Expansion gap to the left of every second pillar.

 

[PaulJR]

Looks about right, don't forget to put a DPC in at 150 above ground.
I think the Piers should be adequate, but if you want bigger then put a couple of blocks in at 90° to form a 440 square pier (including the wall thickness) If you do this then fill the void with concrete and maybe stick a few bits of rebar in there as well, should withstand anything short of a tank.

 

[unclebob1]

Thanks! Now to find a brick layer willing to do the job!