General rendering questions.....What type? Where to buy? etc

[valleyboy]

Hi all

I've built some block garden walls. Currently there is a mixture of surfaces; new clean bare block, 10 year old bare block (very dirty), partially rendered blocks (cement scratch coat), damp bare block (retaining walls), and damp block retaining walls that have been partially rendered (cement scratch coat).

I want to have a stab at DIY rendering with the through coloured type of render that you see on new builds everywhere and have some questions:

-Anything I need to be aware of in terms of preparation on the above listed surface types? In particular, the damp retaining walls, I do not want to attampt to seal them, don't care if they are always wet, just dont want to apply a finish that will not be long lasting because of the poor condition of the underlying substrate?

-I have done some Googling and realise that there are various brand names available but so far have been unable to determine which of the following is most suitable: acrylic render, silicone render, monocouche etc?

-Could somebody please suggest a mould repellent variety?

-Where to buy? I have phoned all of my local builders merchants, none of them stock any renders, does this stuff magically appear on housing development sites? Where does it come from? Special order from manufacturing plant? Will I be stung with an MOQ?

If you've got this far... thanks for your patience!

Really would appreciate some advice from somebody in the know please.

ATB
valleyboy

 

[valleyboy]

Any takers please?

 

[noseall]

Don't you think this post would be better served in the "Plastering & Rendering" section?
I'll ask the mods to shift it.

 

[valleyboy]

Thanks for pointing that out; and for taking the time to participate in this thread. I hadn't realised that there was a specific section for rendering, just saw 'all things building' and plonked it in here.

Yes, mods please move if possible. Sorry for the inconvenience.

 

[valleyboy]

Can anybody advise please?

 

[clive12345]

Hello valleyboy
Rendering is best applied to dry , clean backgrounds .Your damp
blocks with water coming through them are (in my opinion )no good.
You could try rendering with sand and cement (minimal cost) ,then if it comes off,nothing lost, in way of money.
I have done some tanking work,but the blocks were dry before i started.
Perhaps somebody else will have a better answer.
Good luck

 

[valleyboy]

Thanks for your comments.

I wonder if there is a method of preparing the surface with some sort of mesh product?

 

[clive12345]

Hello,

Rib lath for sand-cement on bad backgrounds. Does not deal with your damp issue though.

http://www.catnic.com/libraries/document/1028.pdf

 

[valleyboy]

Much appreciated.

I have been reading about tanking slurry and am wondering if it is an option.

Also wondering if the damp substrate is a non-issue if using your suggested lath.