Fireplace Niche Venting
Fireplace Niches & Venting.
Fireplace surrounds & internals totally removed.
The first step in making these niches or blocking up and venting fireplaces is to remove any fire surround that is fixed to the wall and lift fire grate from the floor.The next step is to remove all bricks inside the fireplace taking it up to the lintel which is usually situated about 2 - 3 foot above floor level. This lintel supports the triangle/pyramid of brickwork above this opening and if there is not one in place then one should be fitted.
Building framework & Plasterboarding.
Now we are ready to build any framework necessary to support the plasterboard. We are limited in choice to what width we can have as we are working to brickwork either side, but we have a better choice to the height we can have. We can leave it open from floor level to lintel height, or have a more square look like in photo. Framework must be fixed accurately and level. Fix a sheet of half inch plywood on top of bottom frame to support plasterboard and any weight that will be place on it in future - vases etc. Now fix plasterboard to top and bottom of framework, then dot & dab plasterboard to sides and back internals, on brickwork, making sure that all are square with top and bottom and with each other, also make sure that the niche is central in relation to the whole fireplace.
When boarding up a fireplace and fitting a vent you fix a frame around the perimeter of opening and fix horizontal noggings to support plasterboard and vent. Fix plasterboard to framework. When cutting out hole for ventilation make sure it is central in relation to whole fire breast.
Preparation and Plastering.
Before any skimming commences we must fill all gaps and voids that plasterboard did not cover with a backing plaster (browning, bonding etc) Scrim tape any joints from plasterboard to backing plaster or plasterboard to plasterboard inside niche, this is to reinforce joints and prevents cracking when natural movement occurs, Plasterbead all external corners ready for skimming.
Leave for 24 hours to allow backing plaster to set.
Before skimming apply a coat of diluted PVA (unibond) to all areas apart from plasterboard, leave until tacky to touch, then apply a 2 coat plaster finish.
The photos either side are still drying out as you can see damp patches.