Laths and at least two sound laths above and below. Place the expanded metal over the hole and mark it covering the damaged.Where the damage to the laths is over a small area, expanded metal can be used to bridge any gaps:.When the lath and plaster is to be repaired, the plaster can be cut back to the next frame on each side of the damage, the damaged laths cut away and replacement laths nailed in their place.How much you wish to return the building to its original state. It will probably not be allowed in listed buildings - and Using plasterboard as a replacement - the final decision may depend upon the building itself. between frames), or even a complete area, and Removing a complete section of the lath and plaster (i.e. With a large hole or area of damage, it may be worth thinking about.If the laths are exposed but broken/damaged, the method of repair will depend upon the extent of the damage to the laths. The level of the render well below the surface level of the surrounding plaster to allow spaceĪfter the render layer has hardened, dampen the surface and apply the floating layerĪnd bring the level up to about 3mm (1/8 inch) below the surroundingĪfter the floating layer has hardened, dampen the surface and apply the setting layer of plaster and bring the level up to the surrounding plaster. Then apply a coat of render onto the laths making sure that render goes through between the laths to provide a grip. When the laths are exposed and intact, remove all dust and loose plaster and make sure that the spacesīetween the laths are clear of old plaster.ĭampen the laths and the surrounding plaster using a wet brush or water spray and apply three coatings, the render, the floating and the setting layers (see this other pages for the mixes etc). When a large area of lath and plaster needs to be repaired, a more satisfactory finish will be achieved if proper plaster and plastering The surface of the repair filler should be dampened before covering with another layer. Between each layer, the surface of the repair and the surrounding area should be lightly rubbed down using a fine sandpaper - this needs careĪs lime plaster is extremely soft and easily rubbed away. Each layer must be allowed to harden before applying the next. To overcome this shrinkage, a number of layers of filler may need to be applied to build up the surface. The plaster filler used in the repair may shrink as it hardens, and the surface may pull back from the original plaster level - the deeper the repair, the greater the risk that this will occur. Plaster work - if the filler knife is not wide enough to bridge the repair, use the knifeĪround the edges of it and then work into the middle. Use a wet wide bladed filling knife to level off the new filler to the surrounding The edges of the hole and any cracks, add enough filler so that it is above the level of the surrounding plaster. Use a filling knife to fill the hole with plaster filler, take care to push the new plaster into

Or water spray - take care not to over soak the plaster. Mix up some new plaster filler and before applying, dampen the original plaster at the sides and back of the hole using a wet brush The plaster around the sides of the hole so that the new plaster will have something to stick to - try to avoid having tapered edges where the new plaster will have to taper down to almost no thickness on top of the original plaster. Start by cleaning out all the dust and loose plaster from the damaged area, if the laths are not exposed,Ĭut back the plaster to form a deeper hole - try to undercut The technique for repairing lath and plaster is basically the same whether dealing with lath and plaster walls or ceilings.

Refer to our article lath and plaster construction and techniques for details of basic techniques. lime or cement) have different hardnesses etc which, if mixed, will lead to a repair failing.

Or similar, to the original construction should be used.ĭifferent materials (i.e. When making any repair to lath and plaster, the same type of materials, Repairs to lath and plaster walls and ceilings

Patching lath and plaster walls