Painting a dank, damp, musty old outbuilding
Discussion
I've an old outbuilding that looks to me to be made of 1950's concrete blocks with no DPC. The walls are quite damp. I want to paint it so was thinking:
1 - Remove vegetation growing over/around it.
2 - Reroof and add guttering.
I was thinking of (1) adding a waterproof paint on the outside to stop rain penetrating the walls from the outside and (2) using a limewash paint inside to allow any damp in the walls to breathe out.
Does this sound a good plan, any better ideas?
Thanks.
1 - Remove vegetation growing over/around it.
2 - Reroof and add guttering.
I was thinking of (1) adding a waterproof paint on the outside to stop rain penetrating the walls from the outside and (2) using a limewash paint inside to allow any damp in the walls to breathe out.
Does this sound a good plan, any better ideas?
Thanks.
No need for lime wash paint.
A "proper" emulsion paint has some breathing properties - used for bare / new plastered walls.
A vinyl matt, the usual emulsion, is less apt to breathe.
Use the first and you should be okay.
https://www.screwfix.com/p/fortress-trade-10ltr-br...
Scarletpimpofnel said:
I've an old outbuilding that looks to me to be made of 1950's concrete blocks with no DPC. The walls are quite damp. I want to paint it so was thinking:
1 - Remove vegetation growing over/around it.
2 - Reroof and add guttering.
I was thinking of (1) adding a waterproof paint on the outside to stop rain penetrating the walls from the outside and (2) using a limewash paint inside to allow any damp in the walls to breathe out.
Does this sound a good plan, any better ideas?
Thanks.
I'd start by removing all the vegetation and also digging out around the base so that the soil level is nicely below the floor level etc. Clear any gutters and check they're working and check the roof. Then leave it to see what the actual issue is. Once upon a time it would have been perfectly dry. 1 - Remove vegetation growing over/around it.
2 - Reroof and add guttering.
I was thinking of (1) adding a waterproof paint on the outside to stop rain penetrating the walls from the outside and (2) using a limewash paint inside to allow any damp in the walls to breathe out.
Does this sound a good plan, any better ideas?
Thanks.
Giving that time to dry out or not dry out will basically determine what, if anything you need to do.
It depends on the ground conditions and also the exposure to weather, and also what your hopes and expectations for the building are.
Is it just somewhere out off the rain to store a garden spade and stuff, or will it be a workshop for fine carpentry?
Sometimes vegetation actually keeps some rain off, and also can be nicer to look at than a crude shed. OTOH, ivy and some other plants can do a lot of damage.
There are all sorts of options including cladding the outside or lining the inside.
Sometimes damp proofing the floor is one of the best improvements.
Decent masonry paint is often a good option, you can buy versions which are rain-proof but have some breathability.
Sorting out the roof, with good overhangs and gutters would be the priority?
Is it just somewhere out off the rain to store a garden spade and stuff, or will it be a workshop for fine carpentry?
Sometimes vegetation actually keeps some rain off, and also can be nicer to look at than a crude shed. OTOH, ivy and some other plants can do a lot of damage.
There are all sorts of options including cladding the outside or lining the inside.
Sometimes damp proofing the floor is one of the best improvements.
Decent masonry paint is often a good option, you can buy versions which are rain-proof but have some breathability.
Sorting out the roof, with good overhangs and gutters would be the priority?
I have a solid break outbuilding, it isn't really all that damp, but there are two areas of the wall that are problematic. I have a leaking gutter and there's a tarmac path under the drop, it splashes up and leaves a far bigger area damp than you would think. Then one side has had the ground built up about 50cm against it, that wall is also damp believe it or not!
I get damp inside in winter terribly, when it is cold and wet if you spend and time in there you create moisture and it condenses. It was so bad before Christmas that my kitchen wall cupboards in there were wet to the touch! I run a dehumidifier as soon as I remember.
You will be able to get it so it isn't suffering from damp, but unless it's heated and insulated you're still likely to have issues with damp air and condensation in use.
The advice about cladding is good, that would be a simple fix for a single-skin construction, especially if it could do with an aesthetic overall anyway, but it might not be necessary.
I get damp inside in winter terribly, when it is cold and wet if you spend and time in there you create moisture and it condenses. It was so bad before Christmas that my kitchen wall cupboards in there were wet to the touch! I run a dehumidifier as soon as I remember.
You will be able to get it so it isn't suffering from damp, but unless it's heated and insulated you're still likely to have issues with damp air and condensation in use.
The advice about cladding is good, that would be a simple fix for a single-skin construction, especially if it could do with an aesthetic overall anyway, but it might not be necessary.
MajorMantra said:
Worth considering what's making it damp. Is it actually condensation rather than penetrating moisture? Would improved ventilation help?
It it is chronically damp and you want to reduce the tendency for mould to grow, making your own limewash is extremely cheap and easy.
Yep I'm removing all sources of damp I can and increasing ventilation but damp will still come up from the ground through the blocks as no DPC.It it is chronically damp and you want to reduce the tendency for mould to grow, making your own limewash is extremely cheap and easy.
How do I make my own limewash? ty
OutInTheShed said:
It depends on the ground conditions and also the exposure to weather, and also what your hopes and expectations for the building are.
Is it just somewhere out off the rain to store a garden spade and stuff, or will it be a workshop for fine carpentry?
Sometimes vegetation actually keeps some rain off, and also can be nicer to look at than a crude shed. OTOH, ivy and some other plants can do a lot of damage.
There are all sorts of options including cladding the outside or lining the inside.
Sometimes damp proofing the floor is one of the best improvements.
Decent masonry paint is often a good option, you can buy versions which are rain-proof but have some breathability.
Sorting out the roof, with good overhangs and gutters would be the priority?
Yes agreed. I am adding a new roof, bigger overhangs and gutters but the walls will be still damp due to no dpc.Is it just somewhere out off the rain to store a garden spade and stuff, or will it be a workshop for fine carpentry?
Sometimes vegetation actually keeps some rain off, and also can be nicer to look at than a crude shed. OTOH, ivy and some other plants can do a lot of damage.
There are all sorts of options including cladding the outside or lining the inside.
Sometimes damp proofing the floor is one of the best improvements.
Decent masonry paint is often a good option, you can buy versions which are rain-proof but have some breathability.
Sorting out the roof, with good overhangs and gutters would be the priority?
Scarletpimpofnel said:
Yep I'm removing all sources of damp I can and increasing ventilation but damp will still come up from the ground through the blocks as no DPC.
How do I make my own limewash? ty
Easiest method is just mix some hydrated lime (sold at many builder's merchants for plastering and the like, do not confuse with NHL) with water to the consistency of milk or single cream. How do I make my own limewash? ty
You can also use lime putty (made by slaking your own quicklime) but you don't have to.
Damp is a grey scale.
I've lived in houses with no DPC.
It's not a binary thing, either you have a DPC or your walls will be wet and mouldy.
It's more subtle. The ground may be dry, sodden or somewhere between.
Depending on the porosity of the materials and all that, the moisture level below ground will drive the moisture level above ground.
Depending on the temperature and ventilation in the room, the wall will evaporate a certain amount of moisture harmlessly without dank musty overtones.
Old buildings used to work, but many operated on the principle of having a fire in the hearth.
Lime is alkaline, probably fights mould to some extent by being a biocide?
You can ward off 'musty' by nuking things with bleach periodically.
Depending on the wetness of the ground and all sorts of other factors, the actual rate of moisture getting in might or might not be low enough to use a dehumidifier. A mate has a load of stuff in a container, he's keeping that dry with those chemical moisture absorber things, I was sceptical, but I've been to look and learned.
Of course, if you want to knock it down and build something with a proper DPC, that is valid too!
I've lived in houses with no DPC.
It's not a binary thing, either you have a DPC or your walls will be wet and mouldy.
It's more subtle. The ground may be dry, sodden or somewhere between.
Depending on the porosity of the materials and all that, the moisture level below ground will drive the moisture level above ground.
Depending on the temperature and ventilation in the room, the wall will evaporate a certain amount of moisture harmlessly without dank musty overtones.
Old buildings used to work, but many operated on the principle of having a fire in the hearth.
Lime is alkaline, probably fights mould to some extent by being a biocide?
You can ward off 'musty' by nuking things with bleach periodically.
Depending on the wetness of the ground and all sorts of other factors, the actual rate of moisture getting in might or might not be low enough to use a dehumidifier. A mate has a load of stuff in a container, he's keeping that dry with those chemical moisture absorber things, I was sceptical, but I've been to look and learned.
Of course, if you want to knock it down and build something with a proper DPC, that is valid too!
MajorMantra said:
Easiest method is just mix some hydrated lime (sold at many builder's merchants for plastering and the like, do not confuse with NHL) with water to the consistency of milk or single cream.
You can also use lime putty (made by slaking your own quicklime) but you don't have to.
Thanks I might look at that as a cheaper option.You can also use lime putty (made by slaking your own quicklime) but you don't have to.
OutInTheShed said:
Damp is a grey scale.
I've lived in houses with no DPC.
It's not a binary thing, either you have a DPC or your walls will be wet and mouldy.
It's more subtle. The ground may be dry, sodden or somewhere between.
Depending on the porosity of the materials and all that, the moisture level below ground will drive the moisture level above ground.
Depending on the temperature and ventilation in the room, the wall will evaporate a certain amount of moisture harmlessly without dank musty overtones.
Old buildings used to work, but many operated on the principle of having a fire in the hearth.
Lime is alkaline, probably fights mould to some extent by being a biocide?
You can ward off 'musty' by nuking things with bleach periodically.
Depending on the wetness of the ground and all sorts of other factors, the actual rate of moisture getting in might or might not be low enough to use a dehumidifier. A mate has a load of stuff in a container, he's keeping that dry with those chemical moisture absorber things, I was sceptical, but I've been to look and learned.
Of course, if you want to knock it down and build something with a proper DPC, that is valid too!
Yep agree. I aim to address all sources of the current dampness (new roof/gutters/vegetation/clearing soil away etc. But I know damp will rise up the blocks so don't want to trap it in hence using something lime or clay based inside. tyI've lived in houses with no DPC.
It's not a binary thing, either you have a DPC or your walls will be wet and mouldy.
It's more subtle. The ground may be dry, sodden or somewhere between.
Depending on the porosity of the materials and all that, the moisture level below ground will drive the moisture level above ground.
Depending on the temperature and ventilation in the room, the wall will evaporate a certain amount of moisture harmlessly without dank musty overtones.
Old buildings used to work, but many operated on the principle of having a fire in the hearth.
Lime is alkaline, probably fights mould to some extent by being a biocide?
You can ward off 'musty' by nuking things with bleach periodically.
Depending on the wetness of the ground and all sorts of other factors, the actual rate of moisture getting in might or might not be low enough to use a dehumidifier. A mate has a load of stuff in a container, he's keeping that dry with those chemical moisture absorber things, I was sceptical, but I've been to look and learned.
Of course, if you want to knock it down and build something with a proper DPC, that is valid too!
Dulux weathershield smooth masonry paint.
Not the all seasons one but the normal water based.
Pretty good for external render which is subject to the elements so will be ok inside too.
No paint is going to stop damp coming through walls but if you need to paint it then masonry paint t is better than emulsion.
Trust me, I was a painter for 13 years and I ve been a building surveyor for the last 33 years.
Just get it as dry as you can before you paint it.
Not the all seasons one but the normal water based.
Pretty good for external render which is subject to the elements so will be ok inside too.
No paint is going to stop damp coming through walls but if you need to paint it then masonry paint t is better than emulsion.
Trust me, I was a painter for 13 years and I ve been a building surveyor for the last 33 years.
Just get it as dry as you can before you paint it.
Edited by wilpert on Monday 2nd February 21:32
Dulux weathershield smooth masonry paint.
Not the all seasons one but the normal water based.
Pretty good for external render which is subject to the elements so will be ok inside too.
I paint is going to stop damp coming through walls but if you need to paint it then masonry paint t is better than emulsion.
Trust me, I was a painter for 13 years and I’ve been a building surveyor for the last 33 years.
Just get it as dry as you can before you paint it.
Not the all seasons one but the normal water based.
Pretty good for external render which is subject to the elements so will be ok inside too.
I paint is going to stop damp coming through walls but if you need to paint it then masonry paint t is better than emulsion.
Trust me, I was a painter for 13 years and I’ve been a building surveyor for the last 33 years.
Just get it as dry as you can before you paint it.
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