Advice on expansion joint in garage?

[damanpunk]

Folks,

I'm drawing up plans for my garage at the moment and have a question on vertical expansion joints. The garage will be constructed out of 215mm blocks and one side is acting as a retaining wall (it's going to be built against the boundary line with next doors ground level being higher as the house is on a hill)

As the garage FFL will be below next doors ground level I'd like to avoid an expansion joint if possible. Does anyone know if I can get away without it? The afore mentioned wall is 9.5m long and about 3.3-3.5m high, 215mm wide blocks, rendered externally.

 

[tony1851]

It won't be an expansion joint you need. Unlike clay bricks, concrete blockwork shrinks and cracks.

It is recommended to have movement joints in concrete block walls at 6m to 9m maximum spacing depending on the type of block.

You will be pushing it at 9.5m, though you might get away with it if the mortar is not too strong. Problem is, the movement joint is a line of weakness, though you can get sleeved metal ties which are bedded into the mortar joints.

3m to 3.5m might be a bit high for an unrestrained wall that thin.

 

[damanpunk]

Thanks for that mate, good info!

Where exactly does the movement joint have to start at? Is it above the DPC? I'm sure I've read before you can put mesh in the block courses to remove the need for a movement joint but I can't find it now. With my FFL being below the adjacent ground level I'm trying to prevent any possible leak/moisture paths

 

[damanpunk]

Not sure if it makes any difference but I just re-checked my CAD drawing and the wall height is actually just under 2.8m, doh.

 

[noseall]

How much higher is next doors' ground level in relation to your finished floor level (FFL)?

 

[damanpunk]

Hi, it rises as the wall progresses, I think it'd be about 0.2m at the start and maybe 1m by the end of it.

 

[RonnyRaygun]

You won't need a movement joint if you use bed joint reinforcement in the wall.

Look up Bricktor and Brickforce by Bekaert. Not sure which would be more suitable for your application but they will be able to advise. Probably need the Brickforce SBR which is suitable for exposed situations.

 

[damanpunk]

That was exactly what I was looking for, thanks Ronny.

 

[damanpunk]

So I put my drawings in to a structural engineer but he is saying the length of wall and returns is too great so I'd still need a movement joint.... It's only 9.5 x 4m. I'm confused now as this product appears to specifically remove this need yet he's saying it doesn't?

 

[tony1851]

I'm confused now as this product appears to specifically remove this need yet he's saying it doesn't?

Then go with what your SE advises because if it goes wrong, it's his problem and not yours.

 

[damanpunk]

I absolutely would do that usually but I dot want a movement joint unless there's no way around it as that wall is also tanked/retaining. This is just info I've been given before they provide me with a quote, I work as a steelwork designer so I know that often engineers will specify what they've used before over something new or suggested.