How to treat paint peeling on bathroom doorframe?

[DIYLili]

The paint is peeling at the bottom of the doorframe near the ensuite shower. It was only painted 18 months ago. I’m guessing it means there’s a humidity issue. But not sure what I’m meant to do about this. Does someone have an idea?

 

  

(FYI: I’ve removed the grout around the room to replace with silicone, hence the hole between the wall and the floor tiles,)

[EricL]

Hello @DIYLili 

I'm afraid a coat of paint is no longer going to work in this particular situation. Water has entered the bottom of the door frame which I suspect is made of MDF. This section of your door frame has to be replaced. I suggest having a look at this discussion - How to fix rotten door frame in bathroom by @Fefe1578. This will give you a general idea of what needs to be done in order to repair your door frame before you paint it. 

If you need further assistance, please let us know.

Eric

[DIYLili]

Thanks so much, Eric. Your advise and the link are terrific. I have follow up questions (let me know if you prefer I post them in the other discussion thread you linked me too).

• I am unsure how much I will need to remove of the wood, how would I know? 
• When replacing with another piece of wood, I guess I'm better off removing a square-ish piece from the doorframe, right?
• What type of whoo should I used to replace?
• Should I spray the new piece of wood with the wood hardener? 
• How can I suss out whether it is due to a leak or just exposure to water due to shower use?

[JacobZ]

Hi @DIYLili,

Considering this is a bathroom, I would be much more inclined to remove the entire architrave around the door and put in a material that is suitable. MDF is not a suitable material for use in wet areas, as it is essentially heavily compressed cardboard. Any moisture that gets into it will cause it to bulge, as you can see in its profile.

You would be much better off removing this architrave and replacing it entirely with a H3 treated timber trim like this 66 x 18mm 5.4m H3 Treated Pine FJ DAR Primed LOSP. This material is much better suited to being in a wet environment.

In saying this, if you weren't interested in removing and replacing it entirely, then you would cut it off at least 50mm above this point, where it starts to bulge out and then put a piece of timber, like the one mentioned above, in the gap. This will have far better resistance to moisture than MDF. You'd want to cut the existing architrave off square so that you can replace it with a square cut piece of timber.

There is no need to spray the new timber with wood hardener.

Considering the location of the bulge and the fact that there is no silicone around the base of the architrave, I would say the damage is due to water sitting on the ground and in this seam, not a leak that would require further investigation.

Once the new timber block or new architrave has been installed and painted, then you should seal the bottom of it with silicone to prevent water from getting into this gap in the future.

Let me know what you think and if you have further questions, please don't hesitate to ask.

Jacob

[DIYLili]

Thank you! Off to Bunnings now to get what I need. 
the gap at the bottom is just because I am replacing the grouting and just removed it that day. So this side is all good.