At the chimney opening edge – wedge either a stop strip or temporarily a piece of wood around the chimney opening and trim and remove after setting. This can give a cleaner edge – just make sure the plaster stays nice and flat or it will show up when the wood is removed. Good luck!
Vitcas® Heat Resistant Plaster is a high temperature resistant, smooth surface protection up to 650oC /1200 oF for use on walls and chimney breasts, wall chimney holes and cassette stoves. Should be used in conjunction with Vitcas® Fireplace Rinse.
Make sure you buy high temperature grout or it will literally crack and melt under great heat (aka when you use your fireplace! The grout needs to dry completely before you can use the plaster so give it about 5 days.
Heat-resistant plaster is a smooth, high-temperature plaster. Protection up to 650°C (1200°F) Vitcas Heat Resistant Plaster is a replacement material for gypsum plaster when temperatures are too high for gypsum plaster to remain on the wall.
The maximum working temperature of gypsum is 1,200°C (2,200°F), so higher melting temperature materials would melt the gypsum mold. In addition, the sulfur in gypsum reacts with iron, making it unsuitable for casting ferrous materials.
When designing your wood-burning fireplace, safety is another important consideration in addition to design. The use of wallpaper is not recommended as it will heat up and peel off. Likewise, plastering behind your stove will cause cracks due to the heat.
Both gypsum plaster and plasterboard add fire resistance to the building due to the chemical composition of gypsum. It is hydrous calcium sulfate with the chemical formula CaSO4-2H2O.
Use the Best Plaster
You can order it online at VenetianPlaster.it and even have it tinted to match popular paint colors from Sherwin Williams, Benjamin Moore and Farrow & Ball. We were so pleased with the results of our plaster hood that we decided to use it again on this fireplace.
Plasterboard is officially a combustible material. Materials such as “pink plasterboard” may have increased fire resistance, but this does not make them A1 fire rated (e.g. rated).
Plastering a chimney essentially involves applying a layer of mortar (sand cement) to the masonry. This can be a great finish in a cottage where a slightly ‘raw and finished’ look is the order of the day (where it could look totally flat).
Your chimney breast can be plastered with most interior plasters. The fireplace must be heat resistant. One possibility is to plaster them with external plaster, which is both heat-resistant and paintable.
Normal gypsum plaster often cannot handle the heat generated by a wood stove and may begin to crack or peel, either almost immediately after the stove is lit or through gradual wear.
The plaster should first be applied so that the surface is even, but not necessarily smooth. After 15 to 20 minutes, the surface should be smoothed out. The surface finish must be achieved with the trowel while flotation as the material cannot be sanded dry as the surface is dense and non-porous.
Plastic of Paris (POP) is fireproof. It is heat insulating material. POP does not shrink during adjustment. Therefore, it does not crack when heated or set.