How to get boards straight on a wavy wall?

[Bubben141]

I am in the process of converting a former bedroom into a bathroom. All the walls have been torn down to the tongue and groove boards and will be covered with drywall and wet room panels in the different zones. The tiler wants the walls as straight as possible to use both large tiles and minimal grout. The dilemma is that the tongue and groove boards are slightly warped after their 50 years of construction. The boards are vertical and some are warped along the growth rings. The wall is an exterior wall with 4.5 cm thick tongue and groove boards, so replacing them is not an option. Where it shifts the most, there is a difference of about 15mm between the peaks and valleys over a stretch of about 1.5 meters. I have a slightly crazy idea that one could spray on a kind of adhesive-like material and in this way provide support behind the boards where it indents too much. I could then regulate how far in the board should be pressed into the adhesive by screwing in different amounts. Once the adhesive has set, it will hold like a rock, and I can tighten the screws as needed. I can't extend the walls with an additional 45-stud. It has already been done on the walls where possible. What do you think, is the method possible? Or is there an easier way?

 

[injonil]

The easiest is probably to set OSB first, but of course it builds a little.

 

[Gabbe1]

Start by installing blocks/spacers where needed, if you have a long straight edge and a level you can quickly measure where it needs to be built out. Then you attach 15mm plywood behind the wet room boards, this should result in very flat walls.

 

[Bubben141]

Blocks and spacers were my first thought, but there will be so many different blocks when there is a rule spacing of 30cm and wall surface of 2x4m with full ceiling height. My idea with the joint material was to take a shortcut here to avoid measuring so many points. If I have five blocks in height, it will be a total of about 150, all with different levels, where some might only be 3mm with some extremes over 1 cm.
If I put up an OSB/plywood, I'm afraid it will follow the original wall, and it will still be a bit wavy.

 

[injonil]

OSB evens out the wall if there aren't very large "waves".

 

[mångstekta]

otherwise you can finish plastering then fill the walls with fix or some hardening putty then you'll get it completely smooth anyway!

 

[Västerhaninge 17]

In wet room zone 1, one should not use filler on the wet room boards so...

 

[mångstekta]

but how do you put up the tiles then? tape?

 

[kacke_]

Electric planer and level with?
Then you don't screw it so tightly that they go into the plaster anyway. If you place a screw in a "valley," the screw is likely to go through the drywall before it pulls the board enough to affect the tiling.

Best regards, Marcus

 

[Västerhaninge 17]

but how do you put up the tiles then? tape?

I don't know how you do it, but I don't use filler to attach tiles to walls!

Filler and adhesive (for tiles) for wet areas are not the same products

 

[seniorkonsult]

Stop!
No gypsum in wet rooms, i.e., regular gypsum. Additionally, when screwing gypsum, the screw must not go through the paper. The board will then be loose because it is the cardboard that holds the board. Writing this about the gypsum because gypsum was mentioned above.
Read more in the attached link:
http://www.gvk.se/branschregler/vagg/skivmaterial

 

[injonil]

No gypsum in wet areas, i.e., regular gypsum.

That is not what the regulations say, is it?!

 

[stoif]

Stop! No gypsum in wet rooms, that is, regular gypsum. Also, screwing gypsum should not let the screw go through the paper. The board then sits loosely because it is the cardboard that holds the board. Writing this about gypsum because it was mentioned above. Read in the attached link: [link]

If you read in your link, you will see that regular gypsum can indeed be approved, depending on the moisture barrier.

 

[seniorkonsult]

stoif: Of course, there are still those who use shrinking, loosening plastic mats as waterproofing in the shower today, and if you do, you should probably glue the details that are to be mounted on the wall. GVK constantly changes its regulations. A few years ago, the building authority completely banned the use of cardboard-based gypsum in wet rooms. I have seen countless wet rooms with mold-infested gypsum, especially at fittings.

 

[injonil]

A few years ago, there was a complete ban from the Boverket on using cardboard-covered gypsum in wet rooms.

What are you talking about? You seriously seem to have zero clue.