Izonil to waterproof a cellar for a cinema room

BISHI

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Have just moved into a great house with a great cellar ripe for a home cinema conversion. Concrete floor and plastered cieling in place but the old render and plaster has broken down. Have been looking at membrane tanking solutions but they are really expensive. Then I came accross this -

Izonil Breathable,Waterproof Plaster - Howarth Timber & Building Supplies

Does anyone have any experience of using IZONIL in a basement conversion. I would be grateful for advice...:thumbsup:
 
............no body in the building trade here who's used this stuff ??
 
Hi

Personally i would, and did, avoid using a render as a means of tanking. No matter how good it is its got to start to fail at some point where as a tanking membrane made of non biodegradable plastic if done right should be good for a life time.
 
I'm planning on using something similar in my project. The bottom 1000mm of the building are below ground level. I'm not sure if its the same stuff as I cant remember the name of it, but I've been recommended it by two builders, one being my brother, who have used it on customers houses, and their own.

Personally I'm not 100% sure, the last thing you want is damp coming through the walls when its all finished.
 
Apparently English Heritage are using it for restoration work. It is supposed to be breathable and inibits salt formation. My house is an end terrace, next door has a tanked cellar and on all other 3 sides we are surrounded by hard surfaces. Severn trent have just replaced all the water pipes with modern plastic ones. The cellar has a concrete floor which is dry, salt formation has blown a lot of the existing render. I think the cellar is pretty dry and is in the highest part of the town so is never going to flood. I have been getting quotes of £8000 just to install the membrane ( no plastering or finishing). I think this is prohibitively expensive and was hoping this Izonil stuff offers a cheaper solution. Any more advice would be grateful fellas...:smashin:
 
Hi there,

If you do a DIY tanking job using a direct applied system, and groundwater pressure comes to bear, I would fully expect that you will get water penetration into the internal living space; this because formation of a perfect barrier to water is not simplistic and there are additional factors to consider in addition to product selection.

If groundwater pressure never comes to bear, the space may well be fine but that is the risk you run.

Note that product guarantees for such systems are typically not worth the paper they are written on because failure is inevitably attributed to workmanship and in the event that you did prove that it was product failure, they would likely only supply you with a few replacement bags of the product anyway :devil:

I am suprised in respect of the English Heritage comment. Where tanking systems are applied internally they are totally reliant on a bond with the substrate to which they are applied, as any penetrating water effectively tries to push the product off the wall/floor.

Therefore, such products are designed to form as strong a bond with a substrate as is possible, making them difficult to remove (damaging to the substrate in the removal process) and hence being non-reversible (unlike drainage membranes) and particularly unsympathetic in historic structures.

Last year I was responsible for the design and installation of circa £500k of waterproofing in new and existing structures, many of which are remedial systems where the original waterproofing has failed.

I've inspected a basement cinema with problems of water penetration within the last week, and all I'll say is that I'm bloody busy sorting out others cock-ups so urge you to take caution :lesson:

Edit: PS: I note you're in Leamington Spa, I did a block of five apartments there a couple of years ago (failed waterproofing) and have another property I inspected about two weeks ago (failed waterproofing) which I've yet to provide proposals for.
 
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Interesting reading, for my project the building is above the drain level and I'm having a drainage pipe around the outside of the walls at the base level, below ground to let any water flow away. I'm told its some sort soil pipe with holes in to let the water in, and is buried under gravel.
 
I got the quote for this Izonil work yesterday, £11000 to take out and replace brick stairs and 'Izonil' the walls. TBH for that price a membrane is just as expensive....... don't know what to do !!!! Whilst removing the existing render I discovered that on the 2 walls ( external) where there is no degradation or damage the render has been applied to a breeze block wall. Now I would have thought Breeze block would have really been damaged by moisture penetrating ( unless there is a barrier between it and the original brick). Should I try to un render these walls or just leave well alone.


Jamo, are you based in the midlands. If so I would welcome an inspection or even a quotation if you were interested.
 
Hi Bishi,

Membrane, where installed in association with suitable drainage.. yes this means channels and pumps(!) if correctly designed and installed will provide protection against groundwater pressure coming to bear, meaning that in the event any unforeseen circumstance i.e. burst water main etc. the internal environment would be protected.

This type of waterproofing is lower risk than cementitious tanking because you are not reliant on forming a 100% perfect barrier to water, it can be tested by introducing water into the system, (whereas you can't really flood the ground external of the structure), it will tolerate movement in the structure (rigid tanking won't), is not reliable on the condition of the substrate to which it is applied, is more tolerant of post installation damage so if you sell the property and someone hangs a picture they probably aren't going to affect the waterproofing, whereas a nail in a 'tank'... I could go on but for these reasons, 'drained protection' waterproofing is recognised within British Standard 8102 Protection of Structures Against Water from the Ground, as 'being the most effective and trouble free'.

If you're choosing between tanking and drained protection, go with drained protection.

If you're talking about membrane in isolation (no channels/pumps), this will simply isolate internal finishes from potentially damp walls. This is dampproofing, not waterproofing, and if water pressure should come to bear, it will penetrate into the internal living environment.

In respect of breezeblocks, the use of blockwork is common below ground and these would not be affected by groundwater save for perhaps in the event of agressive groundwater conditions (sulphates) which could affect the mortar, but to be honest I would not worry.

If there is an inner leaf of block, this has either been put up to support a suspended timber floor over (possibly rotten joist ends bearing into damp externals), or is there to aesthetically cover what may otherwise be a damp wall. Personally, subject to it not being structural, I would look at taking it down and gaining back some living space.

Thanks for your offer to quote and we do work nationwide but we are a fairly large firm with overheads i.e. Professional Indemnity Insured design etc. (same insurance your Architect/Engineer carries) which our smaller man and a van competitors never carry and I can guarantee we would come in a fair bit more expensive than the quotes you have already received. Still, If you are interested and wanted indicative costs, PM me your email and i'll send you some further info. I do know a reputable company in the Midlands who may assist.

One other brief comment, use an established firm where the guarantee is actually worth something, and ideally get GPI guarantee insurance (FSA regulated insurance co.) so that if they cease trading and you have a problem, it's covered and you don't have to pay out again. You have no idea of the amount of companies which start up, do poor work and then go bump, leaving all involved totally in the lurch :thumbsdow

Mike, presumably this is newbuild? Much of the failed work that we do address is associated with externally applied tanking systems, and commonly the issues are associated with incorrect land drainage. I've been speaking with an Architect in Notts today on an external tanking scheme with issues, and am at a £3.25m house in manchester with issues next week which I think is also externally tanked.
 
I have contacted Midland tanking and they are coming to have a look next week. Will let you know how I get on ..
 
Any more news? The stuff I have been advised to use is called Vandex BB75. I can't find much about it on here though, loads of info on the net, but no reports of anyone actually using it.
 
I have a tanking firm coming round next tuesday so will pick his brain. As it seems to be as expensive as a membrane I think I will go down that route as it is a more established and proven technology..
 
I specify Vandex BB75 on projects regularly but never as the sole form of waterproofing. It is a cementitious tanking product and is therefore subject to the considerations listed within my post above, reliant on the condition of the substrate etc.
 
I have had an incredibly competitive quote from Midland tanking and they are starting work on the 16th..............Might even be watching movies in there by Christmas ....:smashin:
 

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