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Construction Services

Pyromasse specializes in the construction of North East European masonry heaters, cookstoves and ovens.

Construction Services within Quebec

  1. Construction of masonry heaters, cookstoves and ovens from foundation to chimney top, in new or inhabited residences.
  2. Construction only of the Refractory core, with back- up for the client or mason who would face the core, build the chimney, install the cast iron doors, and prepare a foundation. This allows the auto-constructor to be assured that the complicated refractory core is built correctly with quality materials, while still allowing scope for expression and saving on the facing and chimney work.
  3. Consultation service in the form of email or telephone advice to auto-constructors who are confident enough to build but would like the possibility of daily contact with a professional.

Pyromasse Masonry Heater: Details

A typical Finnish style contra-flow heater built by Pyromasse is 51 inches wide by 42 1/2 inches deep and 8 feet high. It stands on an elevated masonry foundation ( from basement to first floor ) and is served by a masonry chimney, located on either side or at the rear of the heater.

Finnish style contra-flow heater A Finnish style contra-flow heater built in Quebec by Pyromasse.

Refractory core:- A Pyromasse hand built refractory core contains 650 refractory bricks, 150kg of castable refractory concrete, 90kg of refractory mortar, and 75 square feet of ceramic wool. The finished core is 40 inches wide and 33 inches deep.

Materials:- Used on the core are:

Brick; Mariland medium duty.
Mortar; Mount Savage super high mullite Airset.
Castable; Mount Savage Heatcrete 24 ESC.
Ceramic Wool; Vesuvius. RT # 6.

Finnish style down-draught contra-flow refractory core Finnish style down-draught contra-flow refractory core.

The fire box:- is 18 inches wide and 26 inches deep ( 30 1/2 inches deep including 4 1/2 inches for the facing brick around the fire box ) The fire box consists of double-width refractory brick walls, allowing the interior width to be replaced if necessary in the future. ( The refractory brick walls of a fire box should last indefinitely). The 're-linable' interior gives an option of light intervention as opposed to total tear-down should it become necessary to repair the heater in the future.

Fire Box showing sloped floor and double walls Fire Box showing sloped floor and double walls.

The Hearth or Fire Box Floor:-Slopes from both sides and the rear onto a narrow grate, giving a considerable efficiency advantage over 'flat, square-bottomed fire boxes. The fire box can have an opening in its front or rear face, or in both front and rear faces creating a 'see -through' effect. This necessitates the installation of an additional fire box door.

Upper Chamber Oven - Pyromasse offers either 'Black' or 'White' (direct or indirect) secondary combustion chamber bake ovens.( 'White Upper Chamber Construction Experience' ) A high-breed white oven with removable plugs, converting it to a black oven, is also an option. The white oven option takes an extra 175 kg of castable refractory concrete, the 'black' 50 kg. It takes five days for two workers, to build the core, The white oven option extends this by a day. The extra time on the more rudimentary black oven being negligible.

Facing:- Though capable in other facing medium Pyromasse prefers and encourages the facing of its heaters in reclaimed burnt clay brick, specialising in traditional relief detail. A selection of reclaimed bricks and ornamental relief pieces is always available ( See Portfolio: Shop, For Sale ) It takes approximately 850 bricks to face a refractory core. Plus 1000 more for 30 feet of chimney. The hours spent facing the core vary in relation to the complexity of relief detail.

Hardware:- Pyromasse uses only cast iron hardware fabricated by Upo of Finland, a company with over 100 years of experience in casting fixtures for masonry heaters. Catalogue

Foundation:-All masonry heaters must rest upon an adequate foundation. In most Quebec dwellings the heater must rest upon an elevated masonry foundation rising from the footing in the basement 9 feet to the first floor The elevated foundation is built of concrete blocks with reinforced grouted cores onto which is pored a reinforced concrete slab. The obligatory 20 inches of non-combustible flooring in front of the fire box opening is also incorporated into this slab in the form of a counter levered extension to one side. The considerable void within the elevated foundation is used as an ash dump, and is fitted with a cast iron access door, enabling ashes to be removed from the basement foundation annually.

Chimneys:- Pyromasse usually builds a 17" x 21" brick chimney, with an 8" x 12" burnt clay liner tile. The chimney is fitted with a manual shut off damper at 6' or a rooftop shut off damper, operated from inside the home by cable. All chimneys are finished with an air entrained concrete cap ( and if the manual damper is installed at 6', a stainless steel rain hat ). Chimneys can be built with multiple flues to serve other appliances.

International Construction Services - Pyromasse offers a complete or partial international construction service.

This enables the home-owner to build a masonry heater in an area where there is no tradition of masonry heating, and therefore no trained builders. Enquiries can be replied to in French, English, and Spanish.


A masonry heater, if used correctly should last a life time. Misuse however can seriously shorten the life of a heater. Pyromasse offers a 5 year limited warranty on a new heater.

In the past 14 years only twice have I been called out to effect repairs on a heater or chimney I had built. This was undertaken promptly at no expense to the client.
Marcus Flynn.

A Pyromasse heater is guaranteed for 5 years. This guarantee covers all materials and work. The guarantee is negated when :

  1. the heater is not fired according to normal masonry heater firing instructions.
  2. The house changes hands
  3. The heater is used as a construction heater, before the house is finished

Not covered by the guarantee:

  1. the exterior portion of the chimney which is susceptible to unpredictable weathering.
  2. the cast iron Upo grate, which will eventually have to be replaced


Information - General and specific information is provided, where possible in both French and English via the Pyromasse web site.


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