Feb or waterproofer in the render before skim coat?

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trialsbiker42

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I'm looking for a bit of advice as on my current job I have rendered a few internal walls with feb in the mix and skimmed over them. I wet the wall down before I skimmed but it seemed to dry very quick, its been a while since I've had to render internal walls as a few jobs have been dot and dab and a lot have been re-skim jobs over original walls. The last wall on this job I pva'd to slow it going off and it worked well, but I was wondering would it eliminate me having to pva with using waterproofer in the render instead of feb? I have another room to render and skim so if waterproofer is an option I'll go with that. Other plasterers I speak to say different things so its hard to judge which is best.

Thanks
 
No need to pva internal render if use a waterproofer. I used freeflo on the last bit i done and left a week before skimming. Was lovely to skim up.
 
A bit of waterproofer in the summer to help with suction.

None in winter. It's cold and sets are slow as it is.
 
This is where I'm at with rising damp,water will always take the easiest route weather it goes up or down.
For this explanation we will make it simple,
for example you have a single skin brick wall with no damp course that is rendered internal with s&c with waterproofer in.
water is in certain situations can be absorbed by the pourus bricks but then will evaporate out of the bricks,it won't get trapped behind the s&c it will take the easiest route whitch is out the face of the brick not causing any damage.
i don't think water will rise that far up the bricks before evaporating.
i believe a lot of damp instances occur when water/moisture is trying to get out and not in.
eg single skin brick with waterproofed render on the outside,moisture and condensation go into the cold bricks and try to find a path out,it can't because of the waterproofed render,at this point gravity comes into play and all the moisture in the walls gathers at the bottom looking like rising damp.
im not denying that in perfect conditions rising damp can occur I just think there are better explanations for most damp diagnostics,also most damp issues are not as clear cut as the examples above. @D4mp could shed some more light on this:RpS_thumbup:
 
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it's very likely any capilliary action of water up a wall is not via bricks, it's more than likely the old render carrying the water up the wall and soaking the face of the bricks, making it look like the illusion of bricks soaking up water. old lime render is very porous.
 
I'm not being funny but the water is coming from the sky so it's gonna get in higher up first then maybe work it's way down and give the impression it's rising up. But to think that water will rise up through a wall like it's going somewhere is mad why would it go up? It will always go down I'm sure we all know that water runs down hill rather than up. The thing with waterproofer in your rendering was discussed in another thread, should it be in the scratch or top coat or non at all? Well this is where it works and only if it's done correctly. Waterproofer in your scratch and not in the top. When we hear waterproofer we think waterproof, well it's not. Water will get through render but it's designed to, if it's not in the top coat it will get through but not pass the scratch then will dry out. If the top is waterproof it will still get through but not get out then stay and move down or freeze depending on the weather. Houses do not get a rising damp desease, something has changed or broke it's that simple. Finding this out needs investigation with the home owner or knowing what your looking for. I have never used a damp meter in my life to solve any damp problem and 9 times out of ten I don't get the job because a job doesn't exist but I usually get the repair :)
 
I was working in a house last year where they redone their garden, laid stone around some of their house, the level of the outside was a couple of inches higher than floor level inside,water managed to find its way through the wall and crept up as high as about a foot behind their kitchen units, they had to take out their kitchen, re screed the floor and do the wall to 1.2m. the surveyor said it was a case of rising damp.
 
I met a bloke who does damp work a while ago, he said it's mostly a con, so your probably right, he got a damp surveyors ticket and makes most of his wages doing surveys, then gives the work to his dodgy damp specialist mates.:RpS_biggrin:
 
Yes flynnman I agree with some of what you are saying,the one thing I will dispute is "water always runs down" just as an example (nisus and Irish spread will like this one) a very popular and simple way of cultivating a certain Dutch herb, it is called a passive wick system,basically there is a water reservoir situated beneath these said Dutch herbs with multiple material wicks trailing upwards into the growing medium of the plants,there are no mechanical parts just simply water traveling up the wicks defying gravity into the medium then into the roots of the plants:RpS_thumbup:
.https://www.growthtechnology.com/wp-content/uploads/2013/07/wicks.png
 
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