I was rather late discovering a in the seal for the bath. i took the panel off the side to discover the boards (it’s quite a new house, so the boards are MDF of some sort) have been soaking for a while. So, repaired the seal, but the damp from the board seems to be taking ages to shift, any advice?

Some of those giant silica gel bags that you can get for keeping cars de-humidified?

https://www.amazon.co.uk/LARGE-DEHUMIDIFIER-REUSABLE-MOISTURE-ABSORBER/dp/B00AZZB5UY

Keep the bath panel off & the window open/extractor on as much as possible. Blow a fan through when the bathroom isn’t in use, aimed under the bath – obviously beware of live electrics in the bathroom.

Are you sure you’ve sorted the leaky seal?

They “should” have used moisture resistant boards in the bathroom so dry them out and all should be okay. The joists however might suffer….

pretty sure i have sorted the seal.

But Dry them out you say? how do i dry them out? Unfortunately it’s one of these bathrooms with no externall wall / window

Leave the light on and the extractor fan will stay on. There is an extractor fan, right? If not you’ll just have to leave the door open and a window or two elsewhere.

Leave the panel off, run a dehumidifier in the room, or panel on and a couple of open sacks of kitty litter in there near the damp.

Aim a fan heater at them if you have one, leave the window open though.

Have extractor, and now some of those caravan crystal dehumidifier things. Will an oil radiator help?

Quite a new house, maybe check with NHSB (or whoever it is these days) of what the spec should be for the boards?

Also, +1 take off the panel and leave the bathroom door open.

Maybe some damp soaking crystals and have you actually sealed the moisture away, or is it really coming from somewhere else?

Pretty sure I’ve sealed it. Cannot see where else it might come from. There is no sitting water

Air flow is key to drying it out, heat will help. If with some heat and good air flow over the area of concern it is not getting any better and you can’t see water going down to it then you could have a leaky pipe underneath.

Give it a good few days to dry out and feel the boards once you have given it a good air(boards simply could have been stained by the water but now be dry)

Ta, will try all that