Watertight Rendering

alanfrank · 14 Jun 2009

The first floor on the front aspect of my house is weatherproofed with ugly 'concrete' type tiles. I would like to remove them and have the area rendered to match the ground floor. A neighbour has done this but is having problems with damp as apparently underneath the tiles is only a single skin of brick. Does anybody have any suggestions how to resolve this problem?
Thanks
alanfrank

jrplastering · 15 Jun 2009

silicone injections and waterproof rendering

alanfrank · 15 Jun 2009

jrplastering said:
silicone injections and waterproof rendering

Thanks for that but could you give me a bit more detail please. What is silicone injection and how do I do it? Is there any requirement to attach some sort of waterproof membrane, or waterproof cement board ( or something similar) ?
Cheers
Alan

jrplastering · 15 Jun 2009

silicone injection is what it says on the tin silicone injected into the bricks or blocks some where about damp proof level water proof render is again what it says on the tin its just a nice 4 2 1 mix and some waterproofer thrown in to stop its absorbing and letting through water. i would recommend that you get professional help for both aspects but im saying this without knowing how competent you are with your hands. do this both inside and outside and you should be covered for damp. there could be other ways round this problem but i've seen the silicone and waterproof rendered on top so many times and its always done the trick nice solid walls to. hope that helps a bit more sorry its not more explanatory but i recommended you get a pro in to do the work rather than yourself to make sure that it all goes spot on

Micilin · 15 Jun 2009

jrplastering said:
silicone injection is what it says on the tin silicone injected into the bricks or blocks some where about damp proof level water proof render is again what it says on the tin its just a nice 4 2 1 mix and some waterproofer thrown in to stop its absorbing and letting through water. i would recommend that you get professional help for both aspects but im saying this without knowing how competent you are with your hands. do this both inside and outside and you should be covered for damp. there could be other ways round this problem but i've seen the silicone and waterproof rendered on top so many times and its always done the trick nice solid walls to. hope that helps a bit more sorry its not more explanatory but i recommended you get a pro in to do the work rather than yourself to make sure that it all goes spot on

Agree it is a bit much for a DIY job - also I would never put lime in with waterproofer.

alanfrank · 16 Jun 2009

jrplastering said:
silicone injection is what it says on the tin silicone injected into the bricks or blocks some where about damp proof level water proof render is again what it says on the tin its just a nice 4 2 1 mix and some waterproofer thrown in to stop its absorbing and letting through water. i would recommend that you get professional help for both aspects but im saying this without knowing how competent you are with your hands. do this both inside and outside and you should be covered for damp. there could be other ways round this problem but i've seen the silicone and waterproof rendered on top so many times and its always done the trick nice solid walls to. hope that helps a bit more sorry its not more explanatory but i recommended you get a pro in to do the work rather than yourself to make sure that it all goes spot on

Thanks again for your response. I wondered if I could do the silicone injection myself but having made a mess of a bit of internal plaster work I wouldn't ever consider the rendering as a diy project. I'll take your advice and call in a pro.
Cheers
Alan

alanfrank · 17 Jun 2009

Micilin said:
jrplastering said:

silicone injection is what it says on the tin silicone injected into the bricks or blocks some where about damp proof level water proof render is again what it says on the tin its just a nice 4 2 1 mix and some waterproofer thrown in to stop its absorbing and letting through water. i would recommend that you get professional help for both aspects but im saying this without knowing how competent you are with your hands. do this both inside and outside and you should be covered for damp. there could be other ways round this problem but i've seen the silicone and waterproof rendered on top so many times and its always done the trick nice solid walls to. hope that helps a bit more sorry its not more explanatory but i recommended you get a pro in to do the work rather than yourself to make sure that it all goes spot on

Click to expand...

Agree it is a bit much for a DIY job - also I would never put lime in with waterproofer.

Thanks. Ill speak with the plasterer I intend to use and see what his thoughts are. What would you consider to be the problem with using lime?

Alan

Micilin · 17 Jun 2009

alanfrank said:
Thanks. Ill speak with the plasterer I intend to use and see what his thoughts are. What would you consider to be the problem with using lime?

Alan

Most waterproofers spec won't allow lime in the mix. You put lime in to improve workability and make it creamier to rub up. In the first coat, a good waterproofer will help th e workability and you won't be rubbing it up(finishing it)

Lime also sets as a lattice in the render, so it gives it a bit of flexibility, which is another reason to use in in a top coat. I presume that this lattice will interfere with the desired homogenous structure of the waterproof coat , but I stand to be corrected on this.

For a proper seal, no beads, don't scratch but use a scud (spritz, splatter) coat for a key - but usually only need this for tanking where soil etc is banked against the wall.

legs-akimbo · 17 Jun 2009

Micilin said:
alanfrank said:

Thanks. Ill speak with the plasterer I intend to use and see what his thoughts are. What would you consider to be the problem with using lime?

Alan

Click to expand...

Most waterproofers spec won't allow lime in the mix. You put lime in to improve workability and make it creamier to rub up. In the first coat, a good waterproofer will help th e workability and you won't be rubbing it up(finishing it)

Lime also sets as a lattice in the render, so it gives it a bit of flexibility, which is another reason to use in in a top coat. I presume that this lattice will interfere with the desired homogenous structure of the waterproof coat , but I stand to be corrected on this.

For a proper seal, no beads, don't scratch but use a scud (spritz, splatter) coat for a key - but usually only need this for tanking where soil etc is banked against the wall.

Stand corrected...your an idiot, absolutely and categorically without question there is no problem adding lime (hydrated) to a render mix indeed it is to be advised, indeed recomended.
b.j. plastering you dont even know what type of wall (brick) this is !!

Micilin · 17 Jun 2009

legs-akimbo said:
Stand corrected...your an idiot, absolutely and categorically without question there is no problem adding lime (hydrated) to a render mix indeed it is to be advised, indeed recomended.
b.j. plastering you dont even know what type of wall (brick) this is !!

I'll sit corrected, at my age

.

I use lime all the time in rendering, I think it is absolutley to be recommended, and prefer it to any kind of plas. In fact if doing something like wet dashing, I sour the sand and lime for a week or so, if I can , before using it.

BUT I would never use it in a waterproof coat. Sika for example is not very nice to give the sand body, but plenty of other brands are.

Have a look at this Sika Spec for example

http://www.sika.ie/ie_constr_Sika_1_Structural_Waterproofing.pdf

Sika are probably the industry standard for waterproofing render systems in Britain, and their Irish site says the following

" "IMPORTANT CONSIDERATIONS
* Do not mix plasticisers, lime, etc. with Sika 1 mixes.
* NEVER scratch previous coats in render to form a key,
as this may let dampness through. "

I learned this while tanking , damproofing etc for four years for a company in the late 80's.We had to work to British Standards, and as subbies were spot checked by them to keep certification. We had to riddle all the sand and cement together before mixing, etc

If your damp comes through, and your mix is not right, then it is your fault, not the additive manufacturer.

If you can post any link here where a waterproofing admix company recommends adding lime, I'd be interested to see what the technical reasons are

legs-akimbo · 17 Jun 2009

I have comleted tens of thousands of mtr's of rendering and always but always used lime in the mix with or without waterproofer.
I have undertaken jobs where specifics of the schedule have specifically started the ratios of mix aslways with lime.
I have been on huge jobs where samples have been taken away for analysis.
I have never ever ever heard, read or been told of one single solitary problem where lime has caused any problem whatsoever.
I have never worked with a single plasterer who does not add lime to his gauge, in whatever proportion they prefer.
Lime is sold and used by the pallett load.
I would not pay three times over the price of a regular waterproofer, for Sika.
Sika have specialised products I do use, but not waterproofer.
I will check out the specifics on lime from the website of the manufacturer.
I accept there may be instances in specialised applications where lime MAY have an adverse effect but for everyday use then never ever a problem.
Seems you have wasted a good many years labouring under a misaprehension ....

legs-akimbo · 17 Jun 2009

White rino lime.
Walk onto any site in Ireland (when there were sites) and in the stores were pallets of White Rhino Lime, Quinns cement and 5 gallon tubs of waterproofer.

http://www.irishlime.ie/construction.html

Micilin · 17 Jun 2009

legs-akimbo said:
I have been on huge jobs where samples have been taken away for analysis.
I have never ever ever heard, read or been told of one single solitary problem where lime has caused any problem whatsoever.
I have never worked with a single plasterer who does not add lime to his gauge, in whatever proportion they prefer.
Lime is sold and used by the pallett load.
I would not pay three times over the price of a regular waterproofer, for Sika.
Sika have specialised products I do use, but not waterproofer.
I will check out the specifics on lime from the website of the manufacturer.
I accept there may be instances in specialised applications where lime MAY have an adverse effect but for everyday use then never ever a problem.
Seems you have wasted a good many years labouring under a misaprehension ....

I've been wasted for many years, it's true!

I'm not arguing against the benefit of lime at all , I've prpbably posted here before about how to use it rendering and if it has no effect on waterproofing I'll be delighted to know that for sure.

To take your points, which are all well made -

I have comleted tens of thousands of mtr's of rendering and always but always used lime in the mix with or without waterproofer.

Not doubting you at all, but were they all waterproofing jobs. I assume not if the waterproofer was optional

I have undertaken jobs where specifics of the schedule have specifically started the ratios of mix aslways with lime.
Tanking jobs or ordinary render?

I have been on huge jobs where samples have been taken away for analysis. Does size matter

? Were they tanked?

I have never ever ever heard, read or been told of one single solitary problem where lime has caused any problem whatsoever.

If a tree falls in the forest and there is nobody there to hear it .......

I have never worked with a single plasterer who does not add lime to his gauge, in whatever proportion they prefer.

Not really relevant to the technical question though?

Lime is sold and used by the pallett load.

Of course it is, it's used in lime renders and mortars, but again not really an argument as to whether it has a effect on waterproofing

I would not pay three times over the price of a regular waterproofer, for Sika.

Neither would I, unless it was specified! And if any additive could do with the help of lime, it is Sika, but again, hardly a technical comment

I will check out the specifics on lime from the website of the manufacturer.

Let me know which one, because I get a lot of 6:1 sand : lime for rendering, and would be happer if I could use it for waterproofing /tanking too. I add waterproofer to it for ordinary render, because it is a nice admix, gives it body and cost a few pence per metre - I'm not anti lime, just want to learn the reasons for and against!

I accept there may be instances in specialised applications where lime MAY have an adverse effect but for everyday use then never ever a problem. We are not talking about everyday use here, we are talking about making something watertight. If there may be adverse effects, and a good waterproofer will give decent workability, then why introduce the lime in the base coat ? What purpose is it serving? Use it in the top coat for finishing.

I am enjoying the argument, and I am sure there are waterproofers out there in the 21st century that lime will not adversely affect, I just want to learn the facts about it.

I suppose another reason might be that lime improves breathability, which is the opposite of impenetrability(sp), the requirement for tanking.

Micilin · 17 Jun 2009

legs-akimbo said:
White rino lime.
Walk onto any site in Ireland (when there were sites) and in the stores were pallets of White Rhino Lime, Quinns cement and 5 gallon tubs of waterproofer.

http://www.irishlime.ie/construction.html[/QUOTE]

Of course there are, but on that site it says "reduction" of water penetration, not tanking.

I don't see any reference in the mix spec to waterproof additive, do you have a link to a waterproofing product.

Also they seem to reduce the lime content with greater exposure or is it my maths?

It looks like the more exposed, the less lime you use - surely if it was a waterproofer, you would increase the lime with greater exposure?

I'm ready to be convinced, just dish it up!

Micilin · 17 Jun 2009

By the way, alanfrank, I hope you are taking all of this in!

You've caused a Lime Schism.

diynot

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Watertight Rendering

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