Plaster to skirting

[babs]

Ok - Ive read a lot on how plaster should finish just at skirting level so that the wall can breathe etc.......however - my walls are 2 foot thick and the plaster goes right down to the conrete floor, so far as i can see in all rooms of the house. (Not my doing)

Do i need to chip away a couple of inches at skirting level to create this space? Will it help in any way? There is condensation problems in some rooms - currently being kept at bay by the electric ventilation system (not sure if i can name it - advertising etc) and heating within the property.

So - does this part of the walls need removed?
Thanks

 

[MdB]

I believe the gap is to stop the plaster wicking moisture up the wall rather than to let the wall breath though I could be wrong.

I have a similar problem where a new concrete floor has just been poured in without the old plaster being removed at the base of the wall. Not too surprisingly we have damp issues in these walls (which are modern block).

 

[Nemesis]

In my house (prob late 18th c with 19th c additions) originally there were no skirtings, and all plaster reached the floor, which was part flagstones and part suspended timber.

The lime plaster would have allowed any wicked moisture to evaporate.

With modern stuff yes you need a gap - gypsum will simply fail if there is any moisture, and the wood won't like it either.

 

[BMcD]

MdB wrote:

I believe the gap is to stop the plaster wicking moisture up the wall rather than to let the wall breath though I could be wrong.

This is quite right but only if the plaster is bridging the DPC. If it does not ie. the concrete floor has a membrane that comes above any existing DPC in the wall then plastering down to the floor shouldn't cause a problem

 

[babs]

Damp proof course?? Not in this house! There is signs of an elctro (i think thats the right name) system around the outside of the house, but its a mud stone construction from the 1800's. Only damp proof we use is heating and ventilation.

 

[MdB]

I think my house is quite common (on PP UK) in having a DPC in the floor but not in the walls as the floor has been added recently. (Mine is a little different in that the walls are modern (1970) though they still don't have a DPC...). The DPC in the new floor keeps it nice and dry but it doesn't breath so the moisture is forced up the walls. The plaster in the walls covered by the concrete floor helps this process no end....

 

[Matt Green]

MdB wrote:

I believe the gap is to stop the plaster wicking moisture up the wall rather than to let the wall breath though I could be wrong.

This is quite right but only if the plaster is bridging the DPC.

Any plaster at that level cant help but bridge the DPC unless the floors DPM has been lapped up and over it. A DPC has to be above solid floor level to have any effect (otherwise the floor itself would bridge it). Any water beneath the floor's DPM will wick into the plaster at the base of the walls.

The gap (50mm or so) is there to ensure this doesn't happen. It's very easy to detect this problem with a resistance meter as the water doesn't rise that far up the wall and the profile you get is quite characteristic. Other way of spotting it is to look for really tiny skirting boards.

Pretty easy to fix with a hammer and bolster if it's causing a problem. If it isn't....then it's not much to worry about.

Matt

 

[Penners]

I think my house is quite common

Oh dear. How unlike the life of our own dear Queen.

 

[babs]

Right - so in answer to my question.........If i have no obvious problems (apart from condensation) will i continue with tiling once this wall is dry (bathroom) and forget about having to rip any plaster off the bottom of the wall?

 

[Nemesis]

If it ain't broke it don't need fixing...

 

[babs]

I think i'll need to use that philosphy for the rest of this house :lol:

 

[Penners]

It's a good philosophy to apply to any period property issue.

The answer to condensation is warmth and effective ventilation. Since you say that you have both, you seem to have the problem covered.

 

[BMcD]

Matt Green wrote:

BMcD wrote:
MdB wrote:
Quote:
I believe the gap is to stop the plaster wicking moisture up the wall rather than to let the wall breath though I could be wrong.


This is quite right but only if the plaster is bridging the DPC.


Any plaster at that level cant help but bridge the DPC unless the floors DPM has been lapped up and over it.

That's pretty much what I said

This is quite right but only if the plaster is bridging the DPC. If it does not ie. the concrete floor has a membrane that comes above any existing DPC in the wall

 

[babs]

I bumped this one back up because i think it may be helpful for future readers to know that if a wall is damp it may be a minor problem.

If you have plaster to the skirting level and concrete floors, and it seems like there is no way to dry the wall - perservere, remove the outer covering (tiles in our case) leave well alone and give the room plenty of air and heat - i promise you it will dry out! 7 weeks without tiles on the wall, the shower moved to the other end of the bath (now not running straight down the wall) and plenty of ventilation and heat and the wall is completely dry! We have nothing more to do except tile the walls now!

Cheers guys - thanks for the advice - If i didnt have this web site the builder would have ripped off the plaster, covered my walls in black tar stuff (to stop future water penetration!) and re plastered at huge expense to us of course!

Our own research and removal of tiles showed that there was little wrong except badly fixed tiles (allowing water to run through them for many years) and no water seals around the bath.

Fixed for the cost of retiling the bathroom (which needed done anyhow!)

 

[Penners]

the builder would have ripped off the plaster, covered my walls in black tar stuff (to stop future water penetration!) and re plastered

Yes - it's the lazy/ignorant/blinkered (delete as appropriate) builder's equivalent of "take two aspirin and call me in the morning".