Alternatives to drywall

Hi all!

We live in Spain.  Most of the year it is extremely hot and dry, but for a couple of months it's cold and can be very wet (the rain falls in huge amounts over a short time frame).  The only heating we use is a log burner in the main room (the other rooms all come off this one)

We, along with most other people here, have problems with black mould.  The buildings are generally poorly insulated, and even though I try to ventilate (and the current windows are draughty) we have problems with mould behind furniture, at the top of the walls, at the corners of window frames etc.

We will hopefully be able to replace the windows this year with high spec ones, which will make a difference I'm sure, but when we were in the UK, they would have suggested drywalling to increase insulation and solve the damp problems.

I'd rather use natural materials if possible and would like to know if you knowledgeable lot have any ideas I might not have thought of!  

I've attached a picture of the current plaster finish (which I hate because it's impossible to keep clean, hard to paint etc)

I'd love to hear your thoughts please!

I don't like drywall either, so I understand your issue.

It might be different in Spain, but here in the United States we have shiplapped lumber and that makes a great alternative. It is cheap, comes in 10 inch wide widths so it goes up fast, can be painted to any color, can be painted with antimicrobial paint so the back does not mold, goes on with regular tools, is more resistant to rodent chewing than drywall, and being made of wood; is very renewable. To make it even better, a sawmill that makes it is seven miles from my house employing neighbors and friends which just adds to its already many benefits.

It is not as cheap as drywall, but considering its attributes, I use it a lot here.

I would think it depends on what's available where you are.  We recently priced all potential products for our walls and sheetrock (made from gypsum} was our cheapest choice.  It comes in 4X8 sheets and comes in an anti-mold version for high humidity areas.  We tape and "mud" the seams and then either sand or wash it smooth, then paint.  As mentioned, you can get paint that retards mold too.  I would much prefer wood but that stuff is sky high right now so we just couldn't justify using it here.    

I really like batten and board:

https://permies.com/t/192183/permaculture-projects/finish-basement-wall#1589159

Hi Helen,
Could I throw out hempcrete as a possible building source? It has good insulation, is fairly rodent proof, and since it is a lyme base, it cannot grow mold. I'm not sure what the availability is like in Spain, but it replaces pretty much everything in the wall except the studs. You put a lyme based plaster on the inside and out and that is it. It is natural and can last a very long time. And if left to itself, it will return to a fairly alkaline pile of organic matter.

In my experience, black mould is caused by moisture either from a leak or high humidity.
Do you have any overhang with the roof to prevent moisture wicking into the building?

A great alternative too is steel, like is what is used on roofs.

I have used that for a bathroom, and while I was just going for an industrial look it was cheap and easy to do. It also went on fast, was easy to work with, and would last forever in an indoor setting.

In my case I only classed the bottom 3 feet of the wall, but you could also go from floor to ceiling.

Steve Zoma wrote:I don't like drywall either, so I understand your issue.

It might be different in Spain, but here in the United States we have shiplapped lumber and that makes a great alternative. It is cheap, comes in 10 inch wide widths so it goes up fast, can be painted to any color, can be painted with antimicrobial paint so the back does not mold, goes on with regular tools, is more resistant to rodent chewing than drywall, and being made of wood; is very renewable. To make it even better, a sawmill that makes it is seven miles from my house employing neighbors and friends which just adds to its already many benefits.

It is not as cheap as drywall, but considering its attributes, I use it a lot here.

Hi Steve

Thank you for this.  I had forgotten about shiplap; a friend used to have it right through their house, and it was, as you say, easy to install and maintain.  I'll investigate availability!

kay fox wrote:I would think it depends on what's available where you are.  We recently priced all potential products for our walls and sheetrock (made from gypsum} was our cheapest choice.  It comes in 4X8 sheets and comes in an anti-mold version for high humidity areas.  We tape and "mud" the seams and then either sand or wash it smooth, then paint.  As mentioned, you can get paint that retards mold too.  I would much prefer wood but that stuff is sky high right now so we just couldn't justify using it here.    

Thank you Kay!

I have a feeling that it might be the same here.  Wood prices seem to have gone through the roof.

4x8 would be practical, and I like that it can be painted.  I'm going to have a good list of things to price up at our diy store.

Anne Miller wrote:I really like batten and board:

https://permies.com/t/192183/permaculture-projects/finish-basement-wall#1589159

Great thread link thanks Anne!

Lots of ideas and choices on there.  I like the batten and board too, reminds me of libraries in stately homes in the UK!

Matt McSpadden wrote:Hi Helen,
Could I throw out hempcrete as a possible building source? It has good insulation, is fairly rodent proof, and since it is a lyme base, it cannot grow mold. I'm not sure what the availability is like in Spain, but it replaces pretty much everything in the wall except the studs. You put a lyme based plaster on the inside and out and that is it. It is natural and can last a very long time. And if left to itself, it will return to a fairly alkaline pile of organic matter.

You can throw in hempcrete Matt!  I've no idea what it is though ;)

I'm off to do a deep dive on Google and become an expert!

I love that it won't grow mould, that's a big plus even before I start.  Thanks for the suggestion.

Steve Zoma wrote:A great alternative too is steel, like is what is used on roofs.

I have used that for a bathroom, and while I was just going for an industrial look it was cheap and easy to do. It also went on fast, was easy to work with, and would last forever in an indoor setting.

In my case I only classed the bottom 3 feet of the wall, but you could also go from floor to ceiling.

Ooh, I bet that would look edgy and contemporary.  I love cheap and easy to do, as I'm time and money challenged!

My list for investigation is growing longer, thank you for the suggestion ☺️

John C Daley wrote:In my experience, black mould is caused by moisture either from a leak or high humidity.
Do you have any overhang with the roof to prevent moisture wicking into the building?

Hi John,

Yes, we have a good all round overhang.  It's such a common issue here that I think it's a building issue; no insulation, block walls, insufficient damp protection etc.  I've got lots of great suggestions here though, so hopefully might solve ours (fingers crossed)

Hi Helen,

Are those houses old enough to not have a damp proof course?

If you've got rising damp then it'll end up destroying most of these solutions.

It might be possible to retrofit with some sort of polymer injection. If not, I would look at lime based plaster and a dehumidifier to let the walls breathe.

James Alun wrote:Hi Helen,

Are those houses old enough to not have a damp proof course?

If you've got rising damp then it'll end up destroying most of these solutions.

It might be possible to retrofit with some sort of polymer injection. If not, I would look at lime based plaster and a dehumidifier to let the walls breathe.

Hi James,

I'm not sure about the damp course, but I don't think it’s rising damp.  The construction here in Spain is not the same as in the UK where I came from originally, but then nor is our climate... we only get 425mm of rain  in a year, and our wettest month is 55mm, and it's generally low humidity, so that's probably why.

We already use a dehumidifier, but I will definitely look into lime plaster, that seems like a common suggestion, thank your for your help!

If like you said you were interested in natural materials there is always wattle and daub.

Kyle Hayward wrote:If like you said you were interested in natural materials there is always wattle and daub.

Oh now that's an interesting thought Kyle, I remember being impressed when I saw that being put up in a school workshop.  Certainly cheap, and has stood the test of time in many places.  Thank you!

Helen Siddall-Butchers wrote:

Kyle Hayward wrote:If like you said you were interested in natural materials there is always wattle and daub.

Oh now that's an interesting thought Kyle, I remember being impressed when I saw that being put up in a school workshop.  Certainly cheap, and has stood the test of time in many places.  Thank you!

would love to see pics if you choose this method

Kyle Hayward wrote:

Helen Siddall-Butchers wrote:

Kyle Hayward wrote:If like you said you were interested in natural materials there is always wattle and daub.

Oh now that's an interesting thought Kyle, I remember being impressed when I saw that being put up in a school workshop.  Certainly cheap, and has stood the test of time in many places.  Thank you!

would love to see pics if you choose this method

I might need to practice first!