Should I use lime or gypsum plaster in a Glasgow tenement?
The short answer
For external sandstone walls in a Glasgow tenement, lime is usually the right choice, because it lets moisture escape. Gypsum and cement-based materials can trap damp against the stone. On internal partitions and for small patch repairs, gypsum is often acceptable. The guiding rule from conservation bodies is simple: repair like with like.
Key points
- Most Glasgow tenements were built between about 1860 and 1914 with lime plaster on sandstone and lath.
- Lime is vapour permeable and flexible. It lets solid walls dry out.
- Cement renders and some modern plasters can trap moisture and speed up stone decay.
- Listed buildings may need consent for changes to original finishes.
- Lime work costs more and takes longer to dry, so book a plasterer with lime experience.
Why the walls matter
A Victorian or Edwardian tenement has thick, solid sandstone outer walls with no cavity. Moisture gets into the stone from rain and from inside the flat, and it needs a way out. Traditionally, that way out was through soft lime mortar and lime plaster, which let water vapour pass through and evaporate.
The Scottish Lime Centre explains that impermeable materials such as cement trap moisture in the wall. Over time that can cause damp patches, salt staining, blown plaster and faster decay of the stone itself.
Lime versus gypsum at a glance
| Lime | Gypsum | |
|---|---|---|
| Breathability | High. Lets walls dry out. | Lower. Can hold moisture against stone. |
| Flexibility | Copes with slight movement. | More rigid. Can crack on old walls. |
| Drying time | Slow. Weeks before painting. | Fast. Days before painting. |
| Cost | Higher. Fewer specialists. | Lower. Most plasterers use it. |
| Best for | External stone walls, listed buildings, damp-prone areas. | Internal stud walls, plasterboard, new work. |
Where gypsum is fine
Plenty of Glasgow flats have been skimmed in gypsum, and it is not automatically a problem. Gypsum is usually acceptable on:
- Plasterboard, including new partitions and ceilings.
- Internal timber stud walls that are not damp.
- Small patch repairs in rooms that are dry and well ventilated.
The trouble usually comes from skimming gypsum straight over damp or salt-affected external walls, or from cement-based renders inside. If a wall keeps blowing or staining, stop patching and find out why.
Listed buildings and conservation areas
Many Glasgow tenements are listed or sit in a conservation area. If your building is listed, changes to historic plaster, cornices and finishes can need listed building consent. Check the Historic Environment Scotland portal or ask the council before stripping original work. Our guide to conservation area rules covers the outside of the building.
Finding the right plasterer
Ask any plasterer you are considering:
- Have you worked with lime on sandstone walls? Can I see examples?
- What will you use on my external walls, and why?
- How long should I leave the plaster before decorating, and what paint should go on it?
Lime should be finished with a breathable paint, so tell your decorator too. Our ranked table of Glasgow plasterers notes firms with heritage and cornice experience. For prices, see what it costs to skim a room.
Questions
Can I put gypsum over old lime plaster?
It is common, but it is not always a good idea on external walls. Gypsum over damp lime can fail and trap moisture. A plasterer with traditional building experience can tell you whether your wall is suitable.
Does lime plaster stop damp?
No plaster stops damp on its own. Lime helps a wall manage moisture by letting it evaporate. The source of the damp, such as a gutter, pointing or a leak, must be fixed first.
What paint goes on lime plaster?
A breathable paint such as a limewash, a clay paint or a mineral paint. Ordinary vinyl emulsion can reduce breathability.
Is lime plaster more expensive?
Usually yes, because it is slower to apply and dry, and fewer plasterers specialise in it. Ask for a written quote that lists the materials.
Sources
- Scottish Lime Centre: introduction to lime in traditional buildings (opens in a new tab)
- Building Limes Forum: lime plasters and renders (opens in a new tab)
- Glasgow City Council: listed buildings (opens in a new tab)
This guide is general information about Glasgow and Scotland, checked on 3 November 2026. Prices and rules change, so confirm anything important with the organisation named before you act.
