Preparing the GF ceiling

Ground floor ceiling being prepped ready for plastering.

Chalk plaster

We're trying out a new plaster today - it is a chalk - lime mix with polypropylene fibres.

It is a pre-mixed product by Fibrelime.  It comes to site in tubs.

After it has been knocked up with a splash of water.

It works best when a fairly tight coat of approx 2-3mm.  When we tried it thicker than this it was difficult to get it flat, as it was difficult to rule.

A finished wall (and the right hand side of the ceiling - the other side is lime-sand mix).

The fibrelime gives a really nice silky finish - probably the nicest finish of all the mixes we have tried to date.  We are going to stick with this mix for the foreseeable future!

Progress

The bathroom plastered and limewashing underway.

Bedroom 3 also plastered and clay wall limewashed, with window lining also limewashed.

Limewash

Next up is limewash.  This is a pre-mixed version bought from Mike Wye.

This is what it looks like when mixed up.  Like  the casein paint when applied it becomes translucent and looks awful until it dries and becomes opaque.  It is built up in a number of coats, we are doing about 4.  Because it is translucent when applied it makes it very difficult to see where you have been.  It can be used on plaster and on wood.  On the lime plaster it becomes part of the lime plaster, and any cracks completely disappear.  We wet the plaster down before the first coat if it is dry but the limewash can be applied as soon as the plaster can take a brush.  We have not been wetting it down between coats as the water tends to just run off when we have tried.

We are going to mix the next limewash up on site.  There are various ways this can be done, with either lime putty, hydrated lime or hydraulic lime.  We are going to try hydrated lime mixed 1:2 with water.  In the top coat we are adding some raw linseed oil to stop the surface from being dusty.  We are bought 100% linseed oil, as some makes have other additives in them.  We'll let you know how we get on!

Casein paint

We have started trying out alternative paints.  First up is casein paint.  This is a highly breathable paint free from VOCs, acrylics, oils and solvents.  It comes as a powder which you mix with water.  Two coats are recommended and it is more expensive than limewash per coat but less expensive than earthborne clay paint.  The paint produced a nice mat finish but it did not fill into the cracks in the lime plaster, but sat on top similar to a more conventional paint.

Clay plaster

We have used clay finish plaster on both the clay plaster on the straw walls and on the magnesium board.  This clay is made and sold by Womersleys.  When applied it tends to roll off the trowel, it can be applied thicker than the lime plasterers we tried and so on the magnesium board went over the beads better.  It was better when mixed slightly drier on the magnesium board, but the magnesium board still tended to make the plaster dry very unevenly.

It took longer to get a good finish, and it was critical to catch it just right otherwise the surface tended to become dusty and not be bound properly.  It did produce a nice finish which did not crack or shrink back.  Clay plaster does not have a 'set' like lime, it is either wet or dry and it can forever be changed from one state to the other.  This does make it more difficult to decorate, as when you work in the lime wash or paint it tends to absorb into the plaster and make it live again, rucking up the surface.  One suggestion we are going to give a go is applying the limewash with a trowel - could be interesting!

Tadelakt plaster

In the shower room we are using Tadelakt plaster to all walls and ceiling, including the walls in the shower instead of wall tiling.  Tadelakt is a waterproof lime based plaster which comes from Morocco.  The magnesium board has been primed with Magnaprime and a base coat of Limewall applied.  Following this two coats of the tadelakt are applied.

Once this has dried a polishing soap is brushed on.

This soap is made with tree oils, especially olive oils.

The surface is then polished with a special stone to produce a shine.

A second application of the soap is polished up with a lambswool bonnet.

The shower after the first application of polish and burnishing with the stone.

More plastering - master bedroom

Site mixed lime putty / kiln dried sand applied on the studwork partitions.

Undercoat of clay applied to the straw walls.

Lime plaster on magnesium board

The first areas we plastered were in Mike Wye 3/2 lime plaster, which we had some problems with (as already discussed).  The next plaster we tried was site mixed lime plaster.  We mixed this 1:1

Lime putty and

Kiln dried sand.  This sand is slightly courser than the sand used in the Mike Wye plaster and seems to go on the boards slightly better.  We are still having trouble getting over the beads and the plaster is still not drying as evenly as it could.  One theory is there are very slight undulations in the board which mean the thickness of the plaster varies very slightly.  We are also getting some shrinkage cracks as it dries out.

Plastering begins!

At last we have started plastering!  We are starting with lime plaster - premixed from Mike Wye 3/2 mix, which is what we used for the test many months ago now.

The corner beads and stop beads are fitted, ready for the plaster.

Unfortunately it hasn't started as smoothly as we had hoped!  Despite the test being successful back in May we are finding that the lime plaster is going off very unevenly on the boards and the time taken to go off varies massively from board to board.  It is particularly bad around the beads.  This makes it difficult to trowel the plaster off and difficult to judge how much to put on, as it would be a disaster if it all went off at the same time and couldn't all be finished properly.

The first finished room looks good and feels really silky.  We are working with our plasterer to find a way to make the job quicker and easier.  He has tried adding more fat lime putty to the mix, which has helped a bit.

Resistant render pro board

The Resistant render pro board compared with the multi pro board.  It will be interesting to see what the difference is when we plaster them.

Preparing rooms to plaster

Bedroom 2 getting prepped for plastering.

Family bathroom ready for plaster.

Master bed to be prepped.

Bed 4 ceiling already plastered and walls being prepared.

Bed 3 waiting to be prepared.

Planting

The planting at the front has done well this year.

Priming MgO boards

We are using another type of primer on some of the boards - Magnaprime.  This is not a gritty primer like the DG27 but it does control the suction of the boards.

The first place we are using it is in the ensuite.  Here we are using Tadelakt plaster, which a water proof lime plaster that can be used in wetrooms including showers.  This plaster has a different build up to the lime and clay plaster elsewhere and this is the first coat to go on the magnesium silicate boards.  We will say more about the plaster when we get to it - which hopefully will be in the not too distant future.

The second place is in the family bathroom, underneath the wall tiling.

Elsewhere we are still pressing on with the boarding!

Magnesium silicate board

To date we have been using 9mm Resistant Multi Pro XS board for boarding the internal walls and ceilings. However we were unable to get this last delivery and we had Resistant Multi Pro instead.  The difference between the two is that the XS board has four layers of mesh, while the multi pro only has two layers which gives it extra strength.  The extra strength is important if you were using it as a racking board for example but for us it wasn't critical so we gave the multi-pro board a go.  Whilst these  board are less expensive they have not bee  as easy to work with.  They are much more brittle and tend to crack much more easily.  The corners are particularly prone to breaking and are incredibly difficult to fix and keep in tact!

There are various methods that can be used to cut the boards, the most common is by scoring and snapping.  In some cases this is not possible, for example if you only want to take a small strip off or if you need to cut out a socket.  Other methods can be used, for example hand sawing, or jigsawing.  The board are very hard though and tend to blunt everything amazingly quickly!  One really good way of taking a small about off the board is by using these - blacksmiths files/ rasps.

We tried carpentars rasps but they were forever blunting, but these blacksmiths files stay amazingly sharp and you can be very accurate with them.  They don't look much but trust me they're great!  What is even better is that these ones were being thrown out by a blacksmith, so we are giving them a new lease of life!

Preparing the board for plastering

Preparing the magnesium board before plastering (clay/ lime) involves taping the joints between the boards, securing the tape by putting a thin coat of Gypsum plaster over them.  To get this really smooth and flat we found the best way was to mix up the gypsum so it was quite wet and paint it over the tape.

The next step is to prime the whole lot.  Generally we are using DG27 which is a gritty primer.  This controls the suction of the boards and provides a key for the plaster.  We have started preparing some of the boards, so hopefully some can start to be plastered while we are still finishing boarding in other areas.

Still boarding!

We have been cracking on with boarding recently, trying to get to the end! This is the family bathroom,  now complete.

Insulating the first floor

The rest of the floor that wasn't injected with Warmcel insulation (recycled newspaper), is insulated with the DIY bags of Warmcel.  We tipped these in from above and fluffed them up (dusty stuff!), thickness is 100-150mm.

Boarding on GF ceiling complete

Boarding of the GF ceiling now complete.

Airtightness membrane

The last area to put the airtightness membrane was the wall in the master bedroom.

Now complete!