Painting over wallpaper - need Primer, Sealer or Undercoat?

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ADKM

860 posts

Ultimate Geek

#140628 15-Feb-2014 18:18

We've stripped a room intending to paint over the wallpaper. After ringing a few shops to ask about
undercoats etc. we're thoroughly confused. Some say yes, some no - some say oil based ; others say water based.

Not all the wallpaper came off nicely and there was even other wallpaper under the wallpaper. Some of that came off too. It looks like someone was was going to strip that off but eventually gave up. I've sanded it all and filled any holes with Builders Fill. It's all reasonably smooth to touch now.

In some places it's down to the gib and there's quite a bit of 'white stuff' (gib stop?) splashed around on edges and joins.

Can I just paint it now, or should a Primer, Sealer or Undercoat be used? Which would be best to "smooth out' places where paper edges can be seen (even though reduced by sanding) ?

We're intending to use 3 coats and the paint is Guthre Bowron 'Wall & Ceiling Lo Sheen'.

Thanks for any advice.

scuwp

3888 posts

Uber Geek

#987923 15-Feb-2014 18:26

Pigment sealer for sure. But be warned its pretty potent stuff. Covers the multitude of sins and gives a proper base to top coats

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timmmay

20591 posts

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Lifetime subscriber

#987925 15-Feb-2014 18:35

Dulux total prep is a great product.

ADKM

860 posts

Ultimate Geek

#987926 15-Feb-2014 18:39

Thanks.... if we start with (one coat) and it's not the best, can we then apply a pigment sealer or Dulux total Prep - or is it too late then ? And which of those is best ?

mattwnz

20177 posts

Uber Geek

#987944 15-Feb-2014 19:06

Go into resene and ask them. They have all the products you need and good advice, as well as fact sheets on the products you need, and also a NZ company. Going into a general hardware shop selling paint,you are likely to get conflicting info.
If you just got to the resene website, it should also have the fact sheets you need on the products required, as there are often a number of different ways you can go about it.

RunningMan

8964 posts

Uber Geek

#987946 15-Feb-2014 19:07

Don't try applying the top coat - it won't stick properly.

Go for a pigmented sealer first as it will cover pretty much anything, and also stop anything nasty from bleeding through, then a couple of top coats.

IME, tend to use slightly more pigmented sealer than the coverage says on the tin, and a bit less top coat. YMMV though.

Cbfd

307 posts

Ultimate Geek

#987964 15-Feb-2014 19:48

Get off as much wallpaper as you can and then go hire a wallpaper steamer for half a day and clean it up and start with a nice base - then gib stop the inperfections then use resene pigmented selaer it is oil based and pretty amazing brings all the fibrestuff to the front then you sand it off and away you go :)

Oncop53

273 posts

Ultimate Geek

#987967 15-Feb-2014 19:58

Definitely use pigmented sealer as the undercoat, I just did this about 2 weekends ago. It can really soak in though, I had to go back and get another 10 Litres. It is quite stinky (turps based) but worth it.

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ADKM

860 posts

Ultimate Geek

#987973 15-Feb-2014 20:12

Thanks for all the advice and suggestions. Lots to think about. But with an oil based pigmented sealer can you still use the water based paint we've bought ?

Cbfd

307 posts

Ultimate Geek

#987977 15-Feb-2014 20:18

Yer you sure can - since its an undercoat just use cheap brushes or roller to apply as it takes ages to clean them properly - also recommend wearing disposable gloves easier to clean the hands etc

Jaxson

8044 posts

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#988032 15-Feb-2014 22:52

Have great ventilation with that stuff and be prepared to sleep elsewhere for a few nights.
It really is pretty insane. Covers well though.

That dulux prep may be worth looking into instead.

ADKM

860 posts

Ultimate Geek

#988060 16-Feb-2014 01:16

Sounds like gasmasks needed... but I'll take the advice and look at both Dulux and the other.

Glad we didn't just go ahead - well we did but in another room where where the wallpaper wasn't removed. Results are OK.. biggest hassle was removing the masking tape to find paint had crept in under it.

Mega 10 has rollers for $5 which we can bin afterwards... thanks for tip on gloves.

RunningMan

8964 posts

Uber Geek

#988072 16-Feb-2014 07:48

Can can definitely use water based paint over the pigmented sealer.

As far as cheap brushes and roller sleeves go, I wouldn't recommend going for the real cheapies. The cheap ones tend to fall apart as they wear, leaving bristles etc. in your paint. The brushes also splay and wear, making it more difficult to cut in accurately. You don't need the mega dollar top of the line, but I'd spend a little extra and get a better finish and less frustration.

Another trick is rollers / brushes that have been used for a top coat, and you are going to do another with the same paint, wrap them in a plastic supermarket bag and put them in the fridge - saves cleaning them out as the paint won't dry in the cold. Just need a few minutes for it to warm up again before use.

EDIT: spelling

Jaxson

8044 posts

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#988209 16-Feb-2014 13:09

Yeah the real cheap rollers are horrible. They break up all through your paint, and will then show up on the top coat also. Get them wet and roll some water somewhere first to see if they're going to malt.

The masking tape edge thing doesn't work so well, especially if you're painting over a textured wall paper. Take your time on edges and often you don't need the tape. Either that or be prepared to try a few tapes to find one that works well enough, but then doesn't take off what it's sticking to underneath either!