Damp in Scullery

[parkview094]

We have finally saved up enough money to start Phase I of putting a 'proper' kitchen into our home.

Clearing out what used to be the Scullery on the weekend, I discovered a couple of areas where the lime plaster was just crumbling away. Scraping away the loose stuff, the brickwork looks and feels dry underneath. The plaster is powdery and certainly not damp to the touch. Have read the various existing damp threads on the forum, so really just wanted a quick sanity check of my logic..


There is a section along the bottom of the (inside of an) external wall. The ground levels on the other side are all original and well beneath the original slate DPC, but there is a drain here which takes both rainwater from the roof (3 storeys up) as well as the bathroom and temporary kitchen wastes, so I suspect this is historic as the drain was blocked when we moved in 2 years ago.


The other section is in the corner of the room on an entirely internal wall. The gas pipe that runs round the base of the wall is quite corroded where the plaster has come off, so it has clearly been wet here for some time. Again, however, scraping all the loose stuff off, everything seems to be dry underneath. Before we bought the house, it stood empty for just over a year and for many years before that the scullery was just used as a utility room with a tumble drier. There is no heating in the room and the floor is quarry tile on concrete. My thinking is that probably the temperature extremes and or "stray condensation" from the tumble drier probably built up over the years and collected at the base of the wall.

As everything now seems dry and the remaining plaster is solid, my plan was going to be:

Lime plaster over the damaged bits, skim all the walls so they're smooth and then paint. The plan is to turn this space into a proper utility room, so I was thinking about installing a small radiator to keep the room warmer. Does this sound like a reasonable approach, or is there something else I should check/do?

One thing that was nagging me slightly with re-skimming the walls is that they seem to have been painted in a high-sheen paint. It's hard to see from the photo's but the finish is almost eggshell..



My gut feel is it may be the original paint from when the house was built as the kitchen? is in exactly the same finish. When I was scaping the loose plaster away, there didn't seem to be any evidence of any other layers of paint beneath... is that a needless worry?

 

[malcolm]

Your logic sounds good. Where I have had plaster fail like that the bricks have been sodden wet. If yours are dry the problem has been fixed.

I would be interested in the answer to the skim plaster question too. Haven't got that far myself.

 

[Zebra]

When you say repair the lime plaster and then skim, you don't mean gypsum skim, do you?

 

[parkview094]

When you say repair the lime plaster and then skim, you don't mean gypsum skim, do you?

Well.. I was thinking some form of lime skim/finishing coat, but googling further, this might not be so easy in practice?

 

[Penners]

Broadly I agree with your analysis of the situation, on current evidence. However, I can't help feeling that the once-damp area might benefit from being left exposed to warmth and ventilation for a while, if that were possible - just to be belt-and-braces about its dryness. However, if you're really convinced that it is well and truly dry, I'm probably being over-cautious.

If this is going to be a utility room, then your new radiator should really be supplemented with a good extractor fan. Condensation is always very likely in a utility room - particularly one with any external walls. Effective prevention of this means warming the air (so that it holds more water vapour) and then venting it to outside the building.

 

[paulc]

When you say repair the lime plaster and then skim, you don't mean gypsum skim, do you?

Well.. I was thinking some form of lime skim/finishing coat, but googling further, this might not be so easy in practice?

There are a couple of solutions for skimming with lime - Kreidezeit do a couple of mixes that may be suitable depending on the final finish required. Alternatively, prime the walls with DG27 and then apply a thin coat of 3:2 plaster. Unfortunately, neither are cheap options if you have a large area to cover.

However, the paint that is already on the walls may be a problem as far as breathability is concerned. If the paint is nonporous, then a cheaper primer alternative could be used - I've got a couple of walls & ceilings that have been painted in the past with what looks like an oil based gloss, skimmed with gypsum (the pink stuff), and is scheduled for a make-over in lime. I've got a couple of test panels primed with Febond Blue Grit and an acrylic primer - Both have been skimmed with lime, but only time will tell if it will last. I won't recommend either for fear of being castigated (or worse) here :shock:

I've used Kreidezeit smooth lime finish over DG27 on a small area, and it goes on a treat - Very easy to get a smooth finish, and the plaster can be sanded if there are any ridges to get rid of.

 

[MatthewC]

As regards your logic, if the powdery plaster was quite dry then you are probably right that this is an old defect. The actual failure you have is what happens when the wall has something waterproof at the bottom (vertical tiles in your case) and the water then rises up and over a period of time simply destroys the lime plaster. I had some amazingly hard cement along the bottom of most of my walls (up to even 18 inches high in some places) and this was the result I found.

Make sure the wall is dry completely before you plaster over it - I think it is possible that the powder could feel dry but the wall might still be damp.

Matthew

 

[parkview094]

The actual failure you have is what happens when the wall has something waterproof at the bottom (vertical tiles in your case) and the water then rises up and over a period of time simply destroys the lime plaster.
Matthew

Ah that's interesting, I'm not attached to the quarry tile 'skirting', so perhaps it's worth removing. Would a wooden skirting be any better though?

 

[Zebra]

I wonder what would happen if you tried to remove the paint. Have you had a go? I wonder whether it might take the original lime top coat with it, leaving you with the original lime base coat. Then perhaps you could do a new lime top coat, involving no expensive modern sealers.
On the point of the tumble dryer having caused the damp, don't underestimate the extent to which people can misuse them! Giraffe's sister was using a non-condensing one inside a listed wooden outbuilding, simply venting the steam inside the room! We bought her a condensing one, but let's not get into my terrible troubles with tumble dryers lately, it's been too traumatic.

 

[Tony.]

Make sure the skirting isn't hiding a wall repair that touches the floor, there should be a gap between the plaster and the floor.

I like the idea of a small heater
Is there room for an plinth heater in the kickplate of a base unit? Electric or wet?
Again a fan would be a good idea too.

I would watch the pipes in close proximity to the fuse board in case of leaks!
Good luck

 

[Tony.]

You could also be experiencing water condensing on the pipe work and dripping onto the wall, especially if the pipe goes through the wall and the pipe isn't sleeved.

Good luck