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Posted: Sun Apr 29, 2007 7:03 pm
by mick8332
Hello
I have just dug out for a patio in my garden ,and am about to build a retaining wall about 3 feet high to hold back the soil. I am thinking of using concrete blocks ( the large ones with 2 square holes running down them , I dont know the name ) Will i be able to render the blocks or will the damp get through in the winter and cause it to crack . If so any other suggestions would be appreciated .
Thanks
Posted: Sun Apr 29, 2007 7:57 pm
by lutonlagerlout
if you follow the instruction near the bottom of thispage you wont go far wrong
and yes it will be fine to render it,just use a strong mix with plenty of pva/ronafix additive and a waterproofer
cheers LLL 
Posted: Tue May 01, 2007 6:35 am
by bobhughes
I would use solid blocks or back fill the holes with concrete to give added weight/stability to your wall. Drainage is most important to stop pressure from building up behind.
You may want to do the rendering before you lay slabs as it can be messy.
Posted: Tue May 01, 2007 10:11 pm
by ski
I would add that if possible back fill behind the wall with some garvel or similar and drill some holes through the concrete blocks just big enough to allow a plastic sleeve to fit through. Obviuosly fit these before filling with concrete. a few There should be a concrete footing for the blocks as well. Probably about 200mm deep by 450mm wide. Before it goes off put some re-bar into the full depth of the footing and spaced to match the holes in the concrete blocks. Alternately you could use 100mm concrete blocks laid on their side which will be easier to do than all that filling with concrete and I would expect to be strong enough. Hope that helps.
Posted: Wed May 02, 2007 2:16 pm
by liftfan
Hello,
I've got a similar problem to Mick and would also like to add a fence to the top of the retaining wall.
Has anyone got experience of attaching fence posts to the blocks (the ones with holes in). I was thinking my options were:
1. Concrete fence posts placed into the holes and concreted in.
2. Wooden fence posts placed into the holes and concreted in.
3. Wooden fence posts a bracket concreted into the holes.
Thanks for the advice.
Posted: Wed May 02, 2007 5:39 pm
by dig dug dan
Depends what type of fencing you are using. If it is closeboarded, then concrete is a must, but if i is panels, then why not go for the plastic slotted posts. They are actually stronger than concrete, look nicer, and easier to handle.
I would therfore build the fence once the wall was built, leaving the concrete blocks unfilled, then use the holes to place in your fence posts and construct as you go. Should be a quick and easy way of constructing a level fence(assuming you have laid the wall level!)
Posted: Thu May 03, 2007 9:14 pm
by liftfan
Great reply thanks - i had no idea plastic fence posts existed.
I also like the idea of your crusher - is it good with old council paving slabs as I've got around 40 of them I need to get rid of! Could I crush them and use them to fill next to my retaining wall?
Posted: Fri May 04, 2007 7:01 am
by seanandruby
wouldnt it be easier to use concrete fence posts and concrete gravel boards? then no need to render. :;):
Posted: Fri May 04, 2007 9:13 am
by liftfan
A fair suggestion about the gravel boards!
But, the look I'm going for is a Spanish Villa type. The garden is only about 40ft by 40ft and has a DIY swimming pool in it which I am re-instating it. I'd like clean lines and rendered walls. The fence is a problem as I'd like to have good privacy but with a rendered wall all the way around the garden. That's why I had the idea of putting fence posts into the walls.
I'm open to all suggestions!
Cheers.
Posted: Fri May 04, 2007 7:01 pm
by dig dug dan
I also like the idea of your crusher - is it good with old council paving slabs as I've got around 40 of them I need to get rid of! Could I crush them and use them to fill next to my retaining wall?
Yes it is, and it makes good crushed! it saves skipping them!