Garden wall advice please

[woodworksos]

Hello,

I'm going to build a garden wall which will be 12 metres long x 1.5 to 1.8 metres high x 215mm wide using 140x215x440mm solid concrete blocks.

The wall will be tied into existing wall either end and was going to build double width pillars on the ends and maybe one in the middle for extra strength.

The wall will retain approximately 300mm of ground.

My question is should I put an expansion joint in at the mid point (6 metres) and if I do, what is the best method?

I'm assuming I just end the wall vertical half way insert some expansion foam and then continue wall. If this is correct should I still install the pillar and if so how would this incorporate the expansion joint.

Will the expansion joint weaken the wall?

I haven't decided if I will plaster the wall or leave pointed and bear block face.

Thank you in advance and just ask if you have any questions or require more information.

Cheers 👍😊

 

[tony1851]

For starters, 140 is a little slender for a wall which will be up to 1800 high.

A movement joint would be adviseble at the mid point; just build piers at that position each side of the joint.

 

[woodworksos]

For starters, 140 is a little slender for a wall which will be up to 1800 high.

A movement joint would be adviseble at the mid point; just build piers at that position each side of the joint.

Thanks Tony for the information, the wall will be blocks on the flat, so 215mm wide. Sorry if it wasn't clear. Does this sound okay?

 

[freddiemercurystwin]

http://www.planningportal.gov.uk/permission/commonprojects/fenceswallsgates/ scroll down the page for advice on thickness etc

 

[woodworksos]

Thank you for the link, I should be okay with the additional pillars at the ends and centre at 215mm width.

 

[woodworksos]

Hello,

If I put the 10mm expansion gap between the two pillars in the middle of the wall (approx 6 m either side to corners), should I just leave a 10mm gap and build up corners on each section (4 corners). Or do I need to install foam in the gap or Helical expansion joint stainless steel rods between expansion/movement joint. One end fixed to mortar bed and the other side in a tube to allow movement.

I may not plaster the wall, but if I do, can you get plaster bead. Covers for the 10mm expansion/movement joint?

Any information on expansion joint best practice or options would be really appreciated 😊

 

[themiddleagedun]

Personally, I wouldn't bother with an expansion joint for a wall that length, it's only the size off a typical house gable after all.

If you want to fit one the usual way is to cut a strip of fibreboard (flexcell) 12mm wide, place it against one side of the built pillar, then build the rest of the wall to it.

You can get flat bars, with a plastic sleeve to allow movement, called debonding ties, which go across the joint every 2nd course.

 

[woodworksos]

Does this design look okay?

Garden Wall Design

• woodworksos
• 23 Apr 2015
• 1

Would you also recommend using the debonding ties and an expansion joint when I tie the wall in to the two existing walls. Or shoul;d I just tie the walls in with standard ties?

Thanks

 

[RonnyRaygun]

Personally, I wouldn't bother with an expansion joint for a wall that length, it's only the size off a typical house gable after all.

Don't forget that this is a block wall, so it's recommended to install a *contraction* joint at 6m centres.

You can get flat bars, with a plastic sleeve to allow movement, called debonding ties, which go across the joint every 2nd course.

I would definitely use these as it prevents the two parts of the wall from moving independently of each other laterally.

I've just done a calculation and I would advise not going any more than 1300mm high in 215mm blockwork, so it would be sensible to build the bottom at 300mm thick and decrease the thickness to 215mm once you are 1300mm from the top. That way you will not need piers. If you do want to use piers I would recommend them being much closer centres, around 2-2.5m max.
By the way, the piers at the ends are not doing anything once the new wall is tied into the existing walls, so no point having piers in those locations.

Use a minimum 1:5 mortar and dense blocks on a 600mm wide foundation. Take your foundation a minimum of 500mm below ground and have at least 150mm between top of foundation and ground level. It would be sensible to use brick to 150mm above ground, or put in some lapped slates, both in 1:3 mortar to act as a DPC.

Don't forget to put a DPC below your coping if you have one, and ensure that your contraction joint continues through the coping and to the foundation.

I'd use a wall starter at the ends which will allow for differential vertical movement, although the lateral movement should be dealt with by the central joint.

 

[woodworksos]

Personally, I wouldn't bother with an expansion joint for a wall that length, it's only the size off a typical house gable after all.

Don't forget that this is a block wall, so it's recommended to install a *contraction* joint at 6m centres.

You can get flat bars, with a plastic sleeve to allow movement, called debonding ties, which go across the joint every 2nd course.

I would definitely use these as it prevents the two parts of the wall from moving independently of each other laterally.

I've just done a calculation and I would advise not going any more than 1300mm high in 215mm blockwork, so it would be sensible to build the bottom at 300mm thick and decrease the thickness to 215mm once you are 1300mm from the top.

Use a minimum 1:5 mortar and dense blocks on a 600mm wide foundation. Take your foundation a minimum of 500mm below ground and have at least 150mm between top of foundation and ground level. Ensure your foundation is . It would be sensible to use brick to 150mm above ground, or put in some lapped slates, both in 1:3 mortar to act as a DPC.

Don't forget to put a DPC below your coping if you have one, and ensure that your contraction joint continues through the coping and to the foundation.

I'd use a wall starter at the ends which will allow for differential vertical movement, although the lateral movement should be dealt with by the central joint.

Thank you for the detailed information, so just to clarify you would recommend just standard ties or wall starters at the ends. So shouldn't need the debonding ties on the ends just the middle.

Also is it okay to tie in the pillars with wall ties as opposed to overlapping the blocks? This will keep the front face of the wall the same across all courses.


Like this image:-

Untitled

• woodworksos
• 24 Apr 2015
• 1

 

[RonnyRaygun]

Thank you for the detailed information, so just to clarify you would recommend just standard ties or wall starters at the ends. So shouldn't need the debonding ties on the ends just the middle.

Also is it okay to tie in the pillars with wall ties as opposed to overlapping the blocks? This will keep the front face of the wall the same across all courses.


Like this image:-

Untitled

• woodworksos
• 24 Apr 2015
• 1

I think you replied before reading my edited post. I edited to say that if you make the bottom part 300mm thick you won't need piers, but if you do want to use them and stick with a 215mm wall allthe way down to foundation they need to be at much closer centres - (see previous post above).

If using piers I would rather bond them in properly as you won't get the same stiffness from tying to the wall. Some clever block cutting would allow the front face to look the same all the way along.

Yes, wall starters at the ends as they allow for vertical movement - the contraction joint will deal with the longitudinal movement.

 

[woodworksos]

Thank you for the detailed information, so just to clarify you would recommend just standard ties or wall starters at the ends. So shouldn't need the debonding ties on the ends just the middle.

Also is it okay to tie in the pillars with wall ties as opposed to overlapping the blocks? This will keep the front face of the wall the same across all courses.


Like this image:-

Untitled

• woodworksos
• 24 Apr 2015
• 1

I think you replied before reading my edited post. I edited to say that if you make the bottom part 300mm thick you won't need piers, but if you do want to use them and stick with a 215mm wall allthe way down to foundation they need to be at much closer centres - (see previous post above).

If using piers I would rather bond them in properly as you won't get the same stiffness from tying to the wall. Some clever block cutting would allow the front face to look the same all the way along.

Yes, wall starters at the ends as they allow for vertical movement - the contraction joint will deal with the longitudinal movement.

That's great, thank you 👍

I might double up the first few courses (430mm) then once within 1300mm just one coarse (215mm).

Or alternatively just put in extra piers as suggested at 2m intervals.

Thanks

 

[RonnyRaygun]

I should also have said it would be sensible to use engineering brick (class A or B) up to 150mm above ground to act as DPC, although not essential if you are not planning to render the wall.

 

[woodworksos]

I should also have said it would be sensible to use engineering brick (class A or B) up to 150mm above ground to act as DPC, although not essential if you are not planning to render the wall.

Thanks again for the information.

Would it also be an option to use a trench fill foundation shuttered above ground level or alternatively use high density blocks below ground level up to 150mm or install a DPC above ground level?

 

[RonnyRaygun]

I should also have said it would be sensible to use engineering brick (class A or B) up to 150mm above ground to act as DPC, although not essential if you are not planning to render the wall.

Thanks again for the information.

Would it also be an option to use a trench fill foundation shuttered above ground level or alternatively use high density blocks below ground level up to 150mm or install a DPC above ground level?

Best option would be to use a couple of courses of slate in a 1:3 mortar to act as a DPC. That way you can use blocks below. A Visqueen type DPC is not suitable as it will create a weak point in the wall, although, if you are not planning to render it, then really there is no need to worry about a DPC at all.