Insulating under a bath

[bbb]

Hello,
Re-doing our bathroom which is downstairs, single story and with a concrete floor. As it is baltic in there I am putting in heated flooring with Klima insulting boards underneath. The bath will be boxed in so I was wondering whether it is worth putting something underneath it, fibreglass, more klima board etc...

Any suggestions?

Thanks

 

[spacethegas]

stuff it full of fiberglass.

 

[DCPlumbing]

Don't put anything heated around the bath trap. There's a chance it will evaporate the water seal and cause bad smells from the drain.

 

[bbb]

i wont be putting heating elements under the bath, only on open flooring. Fibreglass it is.

THanks
bbb

 

[spacethegas]

helps keep the bath hot longer, especially with steel bath.

 

[Bahco]

What a cracking idea to insulate under the bath.

Does anyone think there could be air flow issues though.

 

[tryitandsee]

Make sure you plug all holes to outside as mice will love it in there making nests.
Also not sure if insulating the underside of the bath will then create condensation problems. Others may know if this would be a problem.

 

[spacethegas]

please elaborate.

i'm always prepared to learn.

 

[tryitandsee]

Quotes from internet
How do you know it is condensation?

It is not always easy to tell. But other kinds of damp, such as rain or plumbing leaks, usually leave a ‘tidemark’. Condensation is usually found on north facing walls and in corners, in cupboards and under work surfaces – in fact wherever there is little air movement.

Cupboards and Wardrobes

Don’t overfill cupboards and wardrobes. Always make sure that some air can circulate freely by fitting ventilators in doors and leaving a space at the back of the shelves.



Spacethegas, these are just general things found under the heading Condensation. My thoughts are that a cold steal bath warmed by hot water when filling the bath will cause some sort of condensation on the underside of the bath, that will not be able to evaporate with all the fiberglass taking up the air space. Whether that matters, I don't know.

 

[spacethegas]

i mentioned it cause i stuffed mine when i fitted it 4 years ago.

probably worth a look behind the panel at some point.

 

[tryitandsee]

Spacethegas, I just found this on 'condensation to industrial unit roofs. My weird logic feels that it is similar to the bath

I guess that spray foam would be the proper answer.

Spray foam insulation is used on a vast selection of properties and buildings to solve condensation problems. Spray foam is easily applied to even the trickiest surfaces and areas, and can eliminate condensation with as little as 1 inch of foam. Because the foam is spray applied, the system has no gaps or weak points and provides a monolithic layer of insulation. This means that spray foam can be applied directly to the surface to be insulated, rather than leaving any air gaps, and leaves no cold bridges. When the foam is applied it will keep the interior temperature of the cladding closer to the interior ambient temperature, meaning that the warmth from inside cannot make contact with the colder surface from the outside, and therefore eliminating condensation. Also, because of spray foam's superior insulating quality and the application method, condensation can be eliminated with as little as 1 inch of foam.

 

[cider]

Spacethegas, these are just general things found under the heading Condensation. My thoughts are that a cold steal bath warmed by hot water when filling the bath will cause some sort of condensation on the underside of the bath, that will not be able to evaporate with all the fiberglass taking up the air space. Whether that matters, I don't know.

If the space is full of insulation how can there be much cold air waiting around to condensate

 

[tryitandsee]

Good point

My only guess is that fibreglass is mainly air, trapped air, although still and not moving, but it will still be cold air

Spray foam is more dense and sticks to the surface insulating it away from the cold air.

 

[Bahco]

Would it not be the same as an insulated cylinder

 

[TicklyT]

Condensation forms when warm moisture laden air comes into contact with a cooler surface. Cooling the air reduces the amount of moisture that it can hold, and the surplus moisture gets deposited as droplets on the cooler surface.

A full bath will be warmer than the air, and insulation will stop moist air in the bathroom circulating through the space around the bath, and possibly coming into contact with relatively cold walls behind it, so condensation should not be a problem.

It could make tracing the source of any leaks tricky. The insulation could 'wick up' any leaks, and deposit water somewhere else where and when you least expect it.