70mm deep damp proofing over 33m - speeding up setting time question

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spredz

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Gents I would appreciate your input -

As described in the title i've got a reasonable area to crack out ASAP this week and it's ridiculously deep. Old style (recently re-done in traditional method for the 17th century cottage i'm in) lime plaster was used wich explains some of the depth of what has been hacked off

The background has had a sika slurry coat and there is now no suction. Conditions are cold and damp, the property is uninhabited.

The guage additive is a pore liner/salt redardant as per the methodology of the company i'm subbying to, i've used frost proofer/accelerator at a ratio of sand cement 3:1 plus 1 full litre of accerator which had no discernable affect. (1L should have sent it off double quick).

I was thinking of adding an additional half bag of extra-rapid cement to each guage making the mix ratio sand cement 3:1.5

This is not the recommended ratio for use with the company's salt retardant additive.


Any suggestions from your experience if that is a good adjustment to the ratio or if there may be side effects from this idea.

thanks,
spredz
 
duuuh

70mm not 700mm as originally stated.

I added half a bag of rapid to each mix today and it stiffened the muck quicker but did not set it much quicker at all.

with no background suction this job is behaving like outside rendering but 7cm thick.
 
what i would do mate is give the area a splatter coat of 3-1 sand and cement which will give you a good key and also a little suction, i wouldn't put anything in with the additives and also keep to the gauge that the company has recommended for the first 2 coats anyway or they will not give you any backup if this go wrong. Your should be able to bring it out in 4 coats max over 3 days and skim it up on the 4th. the thing is, they usually recommend a course sand and a 3 or 4-1 mix which firms up quick anyway.
 
i dont understand why you are replacing lime render with a sand and cement render in a 17th century house... is it not listed??? the reason lime render was used in the first place (they didnt have cement then) but it is a breathable render which allows water to evaporate.
 
I would have thought Render is right, if it is 17th cent ide be surprised if it wasnt listed though ive known some ancient buildings that werent, it would be interesting to know as a conservation officer nowadays wouldnt allow S&C on a listed building.
Lucius.
 
richardbrown said:
Dont let essexandy catch you saying that simply .... he'll have your ball's in the vice lol
Click to expand...

Having seen Simply just before Christmas I think someone had already done that, mind you Monkey does look like he'd have a vice like grip ;)
 
Thanks for your posts gents.

It's a national trust property,

They had it replastered a couple of years ago and it's still very damp. I think some of it was done in lime plaster but in the 2nd room there's evidence of bonding and one-coat around so god only knows exaclty what the last firm did.

I don't need to worry about the debate of using new materials in an old property I'm just on site to deliver what 2 other orgainisations have agreed between them, i'm working off a damp-surveyors report.

The products and methods of the damp company i'm subbying to are making life unnecessarilly difficult. I scratched 2 sections of wall this morning that were still soft as sh1te 7 hours later.

I've worked with depths like this before but never for this company (4th job for them) and their sika-slurry suction killing coat.

the spatter dash jobby might be one to remember for the future, although in this particular scenario i think the depth of material required on the wall holds far too much water for a low/no suction background. Real pain in the arrris job so it is.
 
lucius said:
Is it listed though Spredz
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Don't know for sure. Guess it can't be can it if the national trust have agreed to have it done in sand and cement? Unless someone's dropped a brollock. I'll make discreet enquiries tomorrow....
 
If its got a slurry coat of sika over the top, you might want to look at sika products for going over the top of it. If its sika top seal 107, which is a 2 part mix (powder and liquid) this is totally water proof, if you flick water at it, it runs off.
 
ok this is getting interesting... if its not a listed building and you can use sika products... which are great at holding back the water... but terrible to float over as it takes ages to set and to be honest doesnt give the render much purchase onto the wall... i would suggest you put a tight coat of Maite flexible base coat over the sika and embed mesh into it... the parex maite is waterproof and when set will give you a great base to plaster over
 
I would off dubbed out in 3 or 4 coats to within 15 mm off the desired finish level then tanked it with the sika and then final float coat to the required level while the tanking coat was still green an tacky ;) ;)
 
As warrior said build out the thickness before the tanking goes on is the best way.

But that dont help you now, so stick with the quickset mate or go back to the survyer and see if he will let you membrain the wall and dab them.
 
Thanks for your comments gents.

the sika slurry just says sika slurry on it from memory but it is totally waterproof.

I didn't get to talk with any of the contacts on site that I usually speak to, to ask about if it's listed yet.

The render additive is a salt retardant pore liner that allegedly allows water vapour to pass through as vapour, it's not a waterproofer as such - it makes the render behave very differently to what i'm used to.

I got the best results simply sticking to the flippin manufacturers guidelines like simplybesty suggested (which i usually do but was trying to dope it this time) and a combination of knocking up the muck extra double thick and wrestling it up the walls. This gave good results and a reasonable setting time. Not enought to be able to complete any wall sections the same day, but much better than the doped attempt.

I think the extra rapid and the accelerator (used seperately) were in actual fact not just ineffective but made the situation worse by having a retardant effect on the company's additive. These were both therefore timewasting blunders on my part.

All suggestions above are excellent but not how the company operates so i can't do them in the future. If I had free reign then i would have used different products and methods.

cheers
Spredz
 
Can't you press some exmet sheets into each coat you do. Surely at that thicknes you'll end up with a load of cracking.
 
lucius said:
Is it listed though Spredz
Click to expand...

This is an old post but I can confirm that the property IS listed and owned by the National Trust and they signed a contract to have it DPC injected and re-rendered with modern sand and cement and additives (given that traditional methods had failed miserably).

I presume from your question that some heritage resoration law has been broken?

cheers
spredz
 
spredz said:
lucius said:
Is it listed though Spredz
Click to expand...

This is an old post but I can confirm that the property IS listed and owned by the National Trust and they signed a contract to have it DPC injected and re-rendered with modern sand and cement and additives (given that traditional methods had failed miserably).

I presume from your question that some heritage resoration law has been broken?

cheers
spredz
Click to expand...

Thats the thing, they aren't laws, more a set of guidelines, and there are different levels of historic importance too.

Its to do with being sympathetic to the building in general.
 
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