Do I need to prime between the base coat and the top coat

Andyoxon

New Member
We have applied the base coat EWI-225 premium base coat in 2 stages with the mesh in between we are going to apply EWI silicon render-075 as the top coat; do we need to apply a primer? I spoke to EWI and they said it’s optional!? No real explanation

So I wondered what you guys think, do I need to prime and if so why and why might it be optional?

Cheers
 
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It is usually colour coded to match your silicone. The reason is as you rub it up the aggregate rolls on the base and when it is all dried there is a risk of the base coat colour showing through the scratches.
 
Thanks Rigsby that makes sense, the base coat looks cream and the silicon is pure white the guys doing the job for me don’t intend to apply a primer. I am trying to work out if I should tell them to do it, will cost me more money but they seem to think there’s no need.

Oh and Carl I like Eddy Murphy but not sure what he knows about Render!

Dan thanks at least I’m not the only one who doesn’t think it’s clear cut
 
Thanks Rigsby that makes sense, the base coat looks cream and the silicon is pure white the guys doing the job for me don’t intend to apply a primer. I am trying to work out if I should tell them to do it, will cost me more money but they seem to think there’s no need.

Oh and Carl I like Eddy Murphy but not sure what he knows about Render!

Dan thanks at least I’m not the only one who doesn’t think it’s clear cut
Just leave them alone and let them do their job ffs!
I take it they have come recommended??
 
Ok boys simmer down, I’m rebuilding and extending my house and I doing a lot of it myself and so far when I’ve taken the word of trade people working on my home as gospel,from people with the attitude of Cockney 1 and Nath80,it’s all gone to s**t Ffs.
If a manufacturer like EWI can’t justify and explain why you need a product that they manufacture and sell, then how can anyone else apart from trial and error. Hence why I’m asking here to get a unbiased opinion from people who use these products every day.

It’s my house and my money and I’ve lost a lot of it putting right big mistakes made by a number of builders, plumbers that have assured me they know what they are doing and for it to turn out they really didn’t.

Anyway I really appreciate the helpful comments from those that made them.
 
Thanks Rigsby that makes sense, the base coat looks cream and the silicon is pure white the guys doing the job for me don’t intend to apply a primer. I am trying to work out if I should tell them to do it, will cost me more money but they seem to think there’s no need.

Oh and Carl I like Eddy Murphy but not sure what he knows about Render!

Dan thanks at least I’m not the only one who doesn’t think it’s clear cut

Eddy Murphy is a guru and a regular on the forum.

Just doesn't use his real name.
 
When we did loads of marmorit they never had a primer but they would make you some if you wanted
 
We have applied the base coat EWI-225 premium base coat in 2 stages with the mesh in between we are going to apply EWI silicon render-075 as the top coat; do we need to apply a primer? I spoke to EWI and they said it’s optional!? No real explanation

So I wondered what you guys think, do I need to prime and if so why and why might it be optional?

Cheers
I’ve used sh1t loads of the stuff and only really prime in warm weather onto their 225 basecoat
Thread closed
 
So it 50-50 to prime or not. Temperature question now the guys want to apply he top silicon coat tomorrow without the primer, the forecast temp wise tomorrow and for the next few day’s is for temps between -2 C nighttime and a high of 7degrees C it will be a bit warmer by Thursday. Would you wait for it to warm up a bit?
 
So it 50-50 to prime or not. Temperature question now the guys want to apply he top silicon coat tomorrow without the primer, the forecast temp wise tomorrow and for the next few day’s is for temps between -2 C nighttime and a high of 7degrees C it will be a bit warmer by Thursday. Would you wait for it to warm up a bit?
Do you not trust their own judgement?.
 
No not really think they just want it finished and get on with next job, also I’ve since read quite a few old posts on this site where most people stated If there’s going to be a frost then don’t render, especially with silicon.
Anyway I trust my judgement, now that I read some more. I told them to delay.
 
Priming it you will be safe but not priming it is a gamble.

But the base and top are light colours unlike a grey base and white top so don’t worry too much if they dont do it.
 
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