Garden Wall

Hi all,

Need some building advice on my garden wall! :confused:

I built a small retaining wall last year to divide up two levels of the garden and hold in some low beds ââ?¬â?? the wall is around 1-1.5 ft high and at the time was constructed of breezeblock with a sand and cement render. This render was painted white to give it a nice Med look, but over the winter we have had terrible problems with water seepage. The render has ââ?¬Å?puckeredââ?¬Â in some areas where the water has got to it, and has split, cracked and fallen off in others where the frost has got to it. I have tried adding a layer of damp coursing between the wall and the soil, but the water just seems to get trapped behind this making the problem worse, I have tried adding a layer of stones behind parts of the wall to aid with drainage, again the same problems. I have tried drilling weep holes into the brick work, to no avail. Ultimately it looks like this is just a bad job that needs to go :(

This spring I am going to redo it and this time I want it to last ââ?¬â?? I donââ?¬â?¢t want to be re-doing it for a third time in a year or two! Now here is where the advice is needed. The problem I have (apart from a limited budget) is that there is nothing wrong with the breezeblock. It is sound, it is solid, it has not moved, split, cracked or done anything else wrong ââ?¬â?? in short, it is doing a great job as a retaining wall. The issue is obviously the render and the water that is seeping in as a result of the soil touching the wall, or from underneath via capillary action through the breezeblock (although it is on a footing, so this seems less likely).

Our new idea is to strip the render off completely, create a wooden shuttering around the wall (say 4-5cm either side) and create an inverted U shape of concrete around the breezeblock (rather like a layer of tooth enamel as an illustration). The concrete would use granodust as the ballast, ensuring that the 4-5cm gap will be filled well (i.e. not with gaps where larger stones have not poured in correctly).

Does anyone have any ideas on this? Does this seem like a good solution? Obviously I don�t want to reinvent the wheel, so tearing down the breezeblocks seems like a bad idea, however, if it is the only way to avoid this problem happening again, I will gladly do it and start again! A little more effort now would save me a lot more headaches in the future!

Thanks for reading! :D :D

 

You need to put in proper weep holes, I use 40mm plastic waste pipe.

Secondly Id excavate behind the wall, pressure wash it then 2 coats of bitumen paint the back of it back filling behind with gravel for drainadge.

Your existing render needs to come off completly and be reedone. Use 4-1 mix with water proofing agent in your render ie feb render mix, Or my personal choice a good slug of SBR as it adds waterproofing and makes a very nice workable mix. Dont want to state the obviuse but wet the wall before you render as breze blocks suck.

Last but not least use concrete coping stones to cap the top of the wall and shed the water.

 

Dig out at the back of the blocks line the back of the wall with a heavy duty waterproof membrane then backfill with the soil, you wont stop water creeping up from below unless you had a damp course when you built the wall.

 

Dave what a nightmare for you I bet you were royally peed off when the render started to look a state. Hopefully you will be able to sort things out without too much trouble and I wish you well with your project.Hel.xxx.

 

Hi all,

Thanks for the support and advice - yes, Hel, it has been nightmare. I did (what I assumed) to be everything right, and weeks and weeks were spent doing it! Not happy!

Pro Gard - so, would you forget about the shuttering/concrete overcoat idea then? Just clean and use the bitumen, drill the holes and render the front again? How far apart would you space the holes?

Walnut - would I not have the same problems of the water getting trapped again next to wall, and not draining away?

Thanks again for your help!

Cheers,

Dave

 

"Pro Gard - so, would you forget about the shuttering/concrete overcoat idea then?"

Yes, It wont work!

"How far apart would you space the holes?"

Every metre but make them a sensible size, Ideally you'd have built them in using waste pipe but youll get away with just using a 25mm bitt.

If your using a non sds normal hammer drill then start off with a 10mm bit folowed by the 25mm so as you dont overload your drill.

 

Breeze blocks Dave? can you still get them, or are we talking those light weight aireated concrete blocks.
Niether sound suitable for a retaining wall to me. Sorry.
For starters they wont take frost if they are wet, and in that position they will be wet.
Personally I'd use concrete blocks, probably the hollow ones that can be filled with wet concrete after laying.
And you do need to allow the water out from behind the wall as pro says.
Then the bitumen coating on the back before refilling the soil.
And pro's concrete coping.
I do tend to go for overkill though, dont like things that dont last. :D

 

Yes, I also like things that last! As I said I am more than willing to look at starting again completely so long as I am not repeating myself again in 2 years time. My great uncle (who owned the house before me) had already built some retaining walls out of brick, which are still there. Needless to say, nothing has happened to them! Maybe a complete rebuild with brick is the way to go.

Pro - what do you think? Give it up and start again?

 

Can you post a picture of the blocks you used, if they are breze blocks then folowing the advice given will be fine. If they are lightweight blocks ie thermailtes then you need to start again.

Keep in mind if you go down the brickwork route that the bricks need to be of a frost reistant classification in order that the faces dont spall.

Personally most of the walls ive built are either solid stone or single skin blocks faced with stone.

Other than the odd manhole or repair job Ive always avoided doing large areas of brick work being that im self taught and my laying rate is slow!

 

I've seen ordinary house bricks, LBC, shattered by frost, and also the old fashioned breeze block.
Engineering bricks are ok as are paving blocks.
The lightweights, celcon or thermalite are definitly only for above DPC, something that a retaining wall by its nature cannot be.

 

Stunning garden there Bobj you can see an awful lot of hard work has gone into that. Did you do it yourself? Hel.xxx.

 

Looking good bobj! My brother did sleepers for his which worked really well, but I have much larger garden than he does so it would cost me a fortune! :(

The blocks are definitely on the light side, I assumed with a full render on them they would be OK. Obviously not, so looks like I am starting again. Ah well, would rather be sure before I start and you live and learn

 

Nice job bobj.

 

Good job Bobj well done.

 

I love your garden Bobj, did you design it?