Earth retaining rendered walls/flower beds

[marky9074]

Hi there,

Last year had the garden done and there are a number of earth retaining walls. These were rendered and a lot has blown off over the winter/spring. Now not all of these are on the earth retaining walls, some are just faces that were exposed to some heavy snow drift etc...

Now a lot of people have commented that the walls should have been lined as they retain earth, but this has not been done. Everywhere is totally populated with plants now, so it is not going to be easy to retrofit something, and to be honest I am quite surprised this was not considered by the buider or the designer.

I am wondering if it would be as simple as just digging out a small section close to the wall, and putting in some sort of liner (pond liner?). Basically what I am asking is what should have been done to do it properly at build time (so I can go back to the builder and moan..), and now given that its totally populated, what options do I have to make good.

Below is a link to my build.. it doesnt show the blown render, but you will get a good idea as to what I am dealing with.

http://bit.ly/kBe5to

Please helpful comments only! I appreciate that its possibly a complete mess, and should have been done differently, but it's done now, and I need to find a workable solution...

Cheers,

Mark

 

[freddiemercurystwin]

//www.diynot.com/forums/viewtopic.php?t=278828

Whether you will get any response from your builder is another matter altogether, depends on their appointment etc.

 

[r896neo]

you can remove the render and apply a liquid dpm like synthapruf or similar which can then be rendered over. 2 coats scratch with waterproofer and float coat.

 

[freddiemercurystwin]

Not a god idea IMO, the synthaprufe will just get blown off the wall in time.

 

[marky9074]

//www.diynot.com/forums/viewtopic.php?t=278828

Whether you will get any response from your builder is another matter altogether, depends on their appointment etc.

That's a very helpful thread, thanks! I wish I had looked a bit further. As has been said, a lot of blown render threads! OK, so I am looking at damage limitation... are we really saying that I need to dig out everything and start again? The main earth retaining walls have blown so its no problem to apply a liquid dpm externally.

Even if I dig out I am unlikely to get a nice clean surface again. If I dug out enough to put DPC sheet and a protection board down would that be enough (and also put liquid dpm externally?).

I guess what I am saying is what would you guys do? It is quite dissapointing that this was a 'no expense spared' build. I really did not expect corners to be cut and potentially having to do it again

 

[marky9074]

Another issue I have (look at the photos) is that most of the walls are curved, so at best I am only going to get sheet in

 

[freddiemercurystwin]

As mentioned the combination of liquid dpm and sheet dpm is belt and braces. If you can only do one or other I would recommend a sheet of dpm. Find me a manufacturer who will recommend a liquid dpm be applied externally and I'd be happy to change my view on it. The fundamental ethos behind liquid dpm's is that the water/earth pressure holds them in place.

Don't know why having a curved wall restricts the application of a liquid dpm by the way. Just a bit more fiddly. If you have concerns about corners of blocks jutting out and the like you could do worse than provide an additional layer of protective barrier between it and the sheet of dpm.

In a commercial situation the back of the wall would have had a skim of render to smooth it out prior to the application of the liquid dpm.

I go belt and braces on everything as the cost/hassle of fixing a problem later generally far out weighs the effort/cost required to do a good job in the first place. but you know that already as this is why you're here.

 

[marky9074]

As mentioned the combination of liquid dpm and sheet dpm is belt and braces. If you can only do one or other I would recommend a sheet of dpm. Find me a manufacturer who will recommend a liquid dpm be applied externally and I'd be happy to change my view on it. The fundamental ethos behind liquid dpm's is that the water/earth pressure holds them in place.

Don't know why having a curved wall restricts the application of a liquid dpm by the way. Just a bit more fiddly. If you have concerns about corners of blocks jutting out and the like you could do worse than provide an additional layer of protective barrier between it and the sheet of dpm.

In a commercial situation the back of the wall would have had a skim of render to smooth it out prior to the application of the liquid dpm.

I go belt and braces on everything as the cost/hassle of fixing a problem later generally far out weighs the effort/cost required to do a good job in the first place. but you know that already as this is why you're here.

Ahh yeah sorry, what I meant was that I would not be able to put in the extra protection board in around the curved bits. So let me get this right.. dig out as best I can.. try and clean up the wall, apply liquid DPM, then a DPM sheet.

Now, should I also apply liquid DPM on the external wall given that I have to take it back anyway (where its all blown...)?

At least I have some sort of idea of the scale of what needs to be done.

Cheers,

Mark

 

[freddiemercurystwin]

Ahh yeah sorry, what I meant was that I would not be able to put in the extra protection board in around the curved bits. So let me get this right.. dig out as best I can.. try and clean up the wall, apply liquid DPM, then a DPM sheet.

Now, should I also apply liquid DPM on the external wall given that I have to take it back anyway (where its all blown...)

The protection board is important as without it the dpm will likely get punctured. I don't know why you think you can't get the protection board in, you know its flexible right so will fit round the curves?

Its pointless applying a liquid dpm to the front in addition to one at the rear.

 

[marky9074]

Ahh no I didnt realise it was flexible.. what is the minimum bend radius or is it really bendy!? Do you have a linky?

What holds it in place? Or is that a dumb question?

Cheers,

Mark

 

[shazauk]

I would have thought the earth itself would hold the board in place?

I'll be using the following liquid dmp to my soil side as suggested by freddymercurystwin, spoke with Everbuild and they confirmed this would be suitable to use.

Paint the back of the wall with a couple of coats of this http://www.toolbank.com/p/EVB90101

Read more: //www.diynot.com/forums/viewtopic.php?t=278828#ixzz1PXNRvLRJ

Good luck with the repairs

 

[freddiemercurystwin]

There are various makes and suppliers, theres a link to one in the other thread. The earth holds it in place.

 

[marky9074]

Thanks everyone...

Just one last thing. I am pretty sure that this not applicable.. but there are no chemical DPC options available to me?

 

[marky9074]

Ok this really is the last question

I am trying to think how I can line the internal walls as quickly as possible so that the plants are disturbed the minimum amount...

Can I use a bitumen based roof adhesive like this:

http://www.buildingchemicalsuk.co.uk/AQUASEAL_Firmafix_Roof_Felt_Adhesive_25L/p227683_437564.aspx

My thinking is I can get the plants out, slap around this sealer, lay some normal liner against it, then refill and replant, all in around 1-2 days. I don't really want to rip all the plants out now at the worst time of the year, and have them hanging around whilst normal liquid dpm dries and wait for blocks to dry out etc...

 

[coliholic]

I don't really want to rip all the plants out now at the worst time of the year, and have them hanging around whilst normal liquid dpm dries and wait for blocks to dry out etc...

So why not delay till say late Aug/Sept or the autmumn when the plants are past their best?

My own addition to this and what we did in my brother's terraced garden was to add a 2 inch sheet of polystyrene insulation board against the wall between the dpm and the soil. It's fairly "waterproof" itself and also protects the dpm from stone damage. Been there three years now and the render's not blown off it (yet??)