Does expanding foam absorb damp?

it certainly does absorb moisture, so a waterproof render is required, or paint if applicable

 

render or plaster, or paint if it's going to be visible - or hide it behind plasterboard

internally it won't suffer the affects of UV and the weather so it's more of a visual finishing to suit

 

if once it has set it is left uncut it is waterproof but once it is cut into in will absorb water.

 

waterproof and water resistant aren't the same thing - most are deemed to be resistant, they certainly aren't UV resistant so aren't intended for long term exposure

 

but as its only being used on the inside wall then foam would indeed be waterproof enough for the purpose. you are making the job more dfiiicult than it needs to be. I therefore question who gives you a "correct answer" for your incorrect answer

 

if points where awarded for pedantry ....

 

no Sean, not pedantry, (i have reported your abusive comment)  Im pointing out the fact that the foam is clearly to be used on the interior wall which means that it will be waterproof enough. therefore as i said your advice is wrong and its overkill for an interior wall.

 

it's a waste pipe, so I assume it starts inside and ends up outside - the foam is probably showing externally, hence FHs comment about tidying it up - outside

I'm aware you have a mission Mick, but please stop trying a make an issue out of a very simple question, and answer

 

more abuse reported.

 

Fathands suggests using foam on the interior wall and render on the ouside, as the foam will not bridge the cavity i feel that he means only rendering up the oytside, that will suffice.

 

Morning Fats. Normal way is to use dpr (mortar with waterproofer added) on the exterior and expanding foam on the inner wall. However depending on the position of the wall (it maybe is north facing and subject to more damp then normal) then it would be dpr on both the inner and outer. If it is a bathroom the waste pipe is situated in then dpr on both inner and outer walls is more then likely indicated - do not use plaster either internally or externally. I believe this aligns with what Mick has already posted.

Sean try actually working on site as opposed to reading books/googling etc, and posting stuff which might cause the op to do more work then is necessary.

 

JP, my grandfather was a master builder, my father was deemed to be the same by definition of his profession, a profession from which I've not so long retired from - I've spent most of my life (not just my working life) on sites all over the world, I've built most of the homes I've lived in, I run a very successful small development and maintenance company, my office is a fairly grubby 5 year old LWB Renault Master .......... whilst this may not suit your desire to antagonise and bolster your point, it is the reality

the question asked if expanding foam absorbs damp - yes it does

it's a council built property, they are oft built either single skinned, or without a cavity - so any wall penetration, sealed internally is likely to see some damp

even if there is a cavity, due to the height of the penetration, the internal cavity outer face will see some moisture - so it is highly recommended that a waterproof, not water resistant finished is applied when EF has been used

I appreciate that you may not have agreed with my methods, this forum is about exchanging ideas and views, perhaps your angst would be more productively addressed to a number of so called trusted members who, based on the quality of their advise, would appear to have learnt their ''trade'' watching a couple of episodes of Sixty Minute Makeover

I didn't come here to bicker ............

 

you didn't start a row FH, nothing to be saying sorry for .....

SBR

 

Best I can say is where there's a hole needs filling, fill it with similar to what was taken out.

Fill it as much as possible with brick and cement if it's in brick or block, leaving sealing for sealers(whether foam or silicone).

With a pipe through a wall, I might stick foam on the pipe in the cavity, for insulation, and to fill where I don't want me cement falling through into the cavity when applying it.

And for anyone's information( or Sean's to be more precise) I don't get info from DIY shows.

I'm old enough to have done this stuff, and improved the methods for my own benefit.

Mr. HandyAndy - Really