Finish on Wallrock Thermal Liner

Finish on Wallrock Thermal Liner

One of the most often asked questions when it comes to Wallrock Thermal Liner is ‘what else do I need to put on top of it’? This question relates to what the type of surface finish you’ll get at the end of the process. There are a number of options and we’ll explore them in this post.


1. Paint it

Wallrock Thermal Liner has a smooth side, which is ready to be painted. So, if you have achieved flat surface with Wallrock Thermal Liner and you are satisfied with it you can paint it. Once you have put Wallrock Thermal Liner up on the wall you do need to leave it for at least 24 hrs to dry before painting.


2. Use Wallrock wallcoverings

Why would you use anything else on top of the Thermal Liner if you can paint it? As Wallrock Thermal Liner is 3.2 mm thick and if your wall isn’t perfectly flat you might get step-like differences between each drop. Most likely it will be tiny, but to a lot of people that’s not acceptable and they would like a flat surface. By overlaying the thermal liner with e.g. Wallrock Fibreliner, Wallrock Premium, Wallrock Trend textured paintable wallpapers (or even Paste the Wall Lining Paper) you can hide most of them. If you aren’t sure what these products are and what they look like get a free sample. Just drop us line.

If you don’t want to overlay the thermal liner with anything else quality filler very often does a good job of masking any problem areas.

3. Use Paste the Wall wallpapers

There are a number of printed wallpapers in the market that you might like and they are fine to use as long as they are paste-the-wall (sometimes called non-woven) wallcoverings.


Why you shouldn’t use normal lining paper or wallpaper

Lining paper or traditional wallpaper expands when wet and tries to shrink when drying. We call it dimensionally unstable. Wallrock Thermal Liner is dimensionally stable though. So, as lining paper or wallpaper is trying to shrink whilst on top of the thermal liner it can pull the corners of the thermal liner off of the wall. We don’t realise it, but the force exerted by the drying wallcovering is capable of it. That’s why you very often get gaps when hanging lining paper. You don’t get this when using Wallrock products as they are all dimensionally stable.




  1. agnes kerr


    I have an issue with cold spot mould in the upper corner wall and slanted ceiling which is directly exposed to the outside elements. It is currently covered in embossed wallpaper which was painted with anti mould paint but it seems to be worse this year. I’ve found the insulated lining papers via internet searches and would like some advise on suitability for the ceiling. What would be the best option for covering the ceiling, is it safe to be in close proximity of lights and can it be painted after with anti condensation paint or similar for added protection? Any advise greatly appreciated

    • OnWall

      Hi Agnes,

      Are you able to determine if the wet spot is a result of condensation or there’s moisture getting in from the outside? It’s critical to the solution you’ll end up using. If you don’t have LEDs and the lights get very hot I wouldn’t consider using Graphite or Red Label Insulating Lining Paper. It’s not so much because of fire risk, but because polystyrene will deform over time. Wallrock Thermal Liner would be a much better liner to use – don’t use KV600 thermal liner on a ceiling though. It can be painted with anti condensation paint, but not sure if it’s needed as that’s the job the thermal liner would be doing. If these paints worked you’d not need any thermal liners.


  2. I’ve applied Wallrock Thermal liner to the cold exterior walls inside a fitted wardrobe which were prone to mould. Just wondering if it’s best to paint an emulsion over the paper to give a better surface for cleaning should any mould reappear or whether the paper itself is wipe clean and therefore not necessary? Many thanks

    • OnWall

      Hi Sadie,

      A short answer is, yes! I’m sure you are doing it already, but please keep the wardrobe’s door open as often as possible especially when leaving for the day.


  3. Ruth Wong

    Hi, I’ve put up thermaliner and it has made a nice smooth surface despite a bad surface underneath. So far so good. But I have tried to paint over it with dulux durable flat Matt caramel sands 5. A paler brown colour. I’ve done 2 coats but now it doesn’t look like a smooth surface at all although it feels flat if I run my hand over it. . So do I have to now cover it all with fibreliner and paint that or does it only look flat if I use a white paint?
    Thanks, Ruth

    • OnWall

      Hi Ruth,

      This is quite unusual. Using something like Wallrock Fibreliner Smooth would certainly solve the issue. I can only speculate on the reasons. It is possible the fine polyester fibres in the thermal liner are being lifted in places by the roller (was the roller used a few times before?) and paint as it passes over the surface – this creates a patch uneven effect. Once the fibres have lifted like this adding more paint will not improve matters. The best solution once thoroughly dry would be to get a sanding pad and lightly sand the surface – ideally one of those big pads so it’s very quick process. Once this is done a further coat of paint should suffice. However, please test it first on a small area. Other possibilities are the paste beneath has not dried out and as the product is breathable it will impact the paint finish or the paint is simply soaking into the surface unevenly. Again, just speculating as this is very unusual.


    • Ruth (Nicola)

      Thank you for your reply.
      The thermal liner had had many days to dry before I painted it. So that can’t be a problem.
      So what I have done is put wall rock fibreliner 150gsm on top and although I haven’t painted yet it looks a much smoother surface.
      Thank you for your suggestions.

  4. I am repainting and would like advice on how to fill holes from picture hooks and from screw holes in the Warlock Thermal Liner (WTL). As the surface moves a little will filled holes stay in place or will the hardened filler pop out of its hole as the WTL moves? Can you recommend a filler that is as flexible as the WTL?


  5. I have fitted wardobes on a north facing exterior wall which are prone to condensation. I have used 7mm thick insulations panels and then painted them with anti condensation paint but it’s still not working. Can I put wallrock thermal paper over the top of them as they would be a nightmare to remove? Plus can I use the anti condensation paint again on top of the wallrock or would that not be necessary? Thanks

  6. Hi – I’ve just installed Wallrock Thermal Liner, and although it’s not the easiest thing to handle I’ve got a great surface now and really thrilled with it. I’m going to to finish it off with the Fibreliner 150 original (for a perfect surface where I’ve got a couple of tiny ‘steps’).

    My question is – do I apply the Fibreliner with the same Thermal Adhesive I put the Thermal on with, or do I use the Wallrock Power Adhesive?

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