Clay plastering vs gypsum

Gypsum plastering is the modus operandi of the common plasterer. It is smooth, fine and cheap and colleges train people how to work it and get it looking as flat as you like. What is there not to like?

On the face of it, if you have a modern house and plasterboard finishes and a professional coming in to do the work then it is an acceptable route to go down. However, if you want a breathable finish that has a natural beauty to it and that is as easy to work as gypsum, but a lot more accommodating for an amateur then clay plaster could well be the way forward.

Clay plaster also has a major advantage over gypsum in older buildings in that it is not hygroscopic. It is breathable (so it lets moisture and water vapour pass through it), but it does not collect moisture like gypsum. Many of these older properties you will find damp patches where the gypsum plaster has swelled up from excess moisture in the walls (through rising damp, wind driven water ingress etc.) Once damp they will stay damp, so you will need to remove them and replaster (hopefully this time with a suitable product like clay or lime).

Clay plasters are:

100% natural and non-toxic

100% biodegradable

Lower in carbon

Natural regulators of internal humidity and temperature

Help to absorb toxins and also neutralise odours


Beneficial to those with allergies and sensitivities

Easy to apply, maintain and repair

So clay plastering, how does it work? Well, basically it is a direct replacement for a skim coat of gypsum. Applied with a plastic edged trowel up to 4 or 5 mm thick is creates a natural finish for your walls. It now comes in a range of finishes from Clayworks (and available through the Eco Home Centre). A standard finish (for painting over) a coloured finish or a mica enriched finish for that added bit of class.

The clay is very forgiving as a material, so if you are not happy with one piece, just go back whenever, wet it up and re-work it. Simple. Once you are happy with the finish simply use the EarthBorn Wallglaze to give a breathable finish that will stop any dusting of the surface (an old complaint from architects and designers – well no more!)

To reduce postage costs the plaster is supplied in dry powder form, so it is just add water and go.

I have a client who is keen to try the plaster in her new home and so we are looking to run a clay plastering course in the near future and so if you are interested please let me know at the centre by emailing

Costs are important of course, so per 25kg bag (enough for 7-8 sq m at 2-4mm thick):

£39.40 – £43.90 for pigmented Mica top coat (dependent on colour)

£34.80 – £39.10 for pigmented top coat (dependent on colour)

£21.50 for plain top coat

£17.90 for a fibre base coat (if required)

Costs are exc. VAT and delivery.