Deer Hill Masonry

Stephen Bushway

MA Lic. 065922
MHA Cert. 003

224 West St.
Cummington MA. 01098

Fax: 413-634-5085

Our Philosophy:

We seek to assist homeowners:

1.    Achieve energy independence.

2.    Have a minimum impact on their air quality

3.    Support their local economy

4.    Live in a healthy indoor environment.

We believe that building cordwood fired masonry heaters and ovens is an excellent means of meeting these objectives.  Along with employing energy conservation strategies and sustainable firewood harvesting, our customers are actually doing a “best practice” in terms of home heating and cooking in the northeast region of the country.  In fact, burning wood for heat isn’t much different than utilizing the sun via solar panels.  While some CO and particulates are emitted in “clean” wood burning, no rare metals have been mined – or ecosystems altered as is the case with the manufacture of photovoltaic panels.  And there’s an elegant aspect to wood burning, as it’s a self sustaining chemical reaction that requires no electricity to initiate or regulate.  And, unlike most other forms of residential heating, sustainably harvested firewood burning is “carbon neutral”: the same amount of CO2 is emitted whether the tree combusts quickly in a heating appliance as when the tree decays on the forest floor.

There are unique advantages to masonry type of wood burning. First and foremost, the quality of heat radiated is gentle and even. Because of its mass, heat created by combustion is absorbed and stored so that surface temperatures fluctuate very little on a daily firing cycle.

Due to the nature of oxygen rich combustion environment,  air pollution is at the low end of the scale of biomass heating appliances.  Indeed, once the firebox has reached operating temperature, all that is seen exiting the chimney is steam.  A properly built masonry heater, burning seasoned wood does not produce creosote so the risks associated with chimney fires is eliminated.

Because of the low surface temperatures, the risk of burning is minimized as well.

Our designs.

We recognize the need for the human spirit to seek harmony and beauty.  Our designs recognize the need for material color and texture harmony and architectural balance (not to be confused with symmetry).

We always seek to create a design that meets our customer’s budget as well. Attention is paid to floor and counter materials and color schemes of the surrounding space.

I welcome the customer’s input in the design process. I first look at the floor plan and see if one of the existing plans from my portfolio will work.  Often an existing “core” plan can be customized to suit the project.  Sometimes it is necessary to design a heater complex from scratch.  I have also successfully designed heater complexes from a sketch and footprint provided: essentially from the outside, in.


Its never too soon to begin the design and planning process.  If house design is a bit of a chess game, heater/chimney location is one of your first moves.   The heater complex footprint, like stairways, is a major floor plan design element.  In more than single floor houses, the chimney must be pass through upper living areas without impacting traffic.  In successful designs the heater complex will be sited in a way to optimize performance, and be a vital anchor and focal point of the space around it.


Cost is impacted primarily by; 1. The actual size of the heater.  2. The options chosen (heated benches, an oven, shelves, niches, etc) 3 and the labor intensiveness of the design.

In the design process we try to meet our customers requirements in the order enumerated above, keeping in mind a structure that is functional and harmonious both as it stands, and in the space around it. We don’t believe it necessary to spend at the high end of the price range for a project to have it be beautiful and harmonious.  The architectural interest and execution of the design are just as important as the materials used.  The choice of facing material is the biggest cost determiner.  A dry layed stone facing can impact the cost of the job over a stucco facing by a factor of 2.  (and also doubling the payback period).   While we enjoy displaying our expertise as stone masons, we also enjoy executing a design with a high “cost-to-benefit” ratio.  Whatever facing material, and design is chosen,  we hold functionality and durability as our primary goals.  There is simply no reason to sacrifice one for the other.

Foundation Requirements

Masonry heaters are heavy and require independent foundation/support system similar to standard site-built masonry fireplace foundations. Finished weight of a typical masonry heater is in the range of 6000-12000lbs depending on size and design. The support system has to be designed according to such load and should comply with clearance requirements of the Fireplace Section of a local Building Code and ASTM 1602-03. Observe clearance requirements of the ASTM 1602-03 for proper location of the heater in relationship to the combustible partitions.

Heater construction in seismic zones may require special additional measures. Discuss them with your heater mason to come up with the solution that will be structurally sound according to the seismic zone requirements and yet will not suffer from thermal expansion problems related to use of steel rebar in the heater facing.

Masonry heaters don’t require combustion air supply from outside or make-up fresh air supply for proper operation, some local authorities or a particular client may require outside combustion air to be brought right to the firebox. In these cases, a supporting structural slab for the masonry heater should be designed with a duct outlet in a place specified by your heater mason.

Another item to be considered while designing support system is ash collection option. Typically, there are two options for ash removal system: dropping ashes down from firebox to an ash box chamber located behind an ash-box door just below the firebox (ashes get collected on the main level) or dropping ashes into a basement ash container through an ash dump well. Units with ash collector located in the basement will need an opening for ash dump well to be incorporated in the design. Consult your client and heater mason/manufacturer for the preferred ash collection option and for proper location of the ash dump opening, if applicable.


Masonry heaters require chimneys. Depending on particular design, heaters can be vented either through a separate freestanding masonry chimney located at the back or either side of the heater, or top-vented through a factory-built stainless steel insulated chimney.

Masonry chimneys:

Require their own footprint, starting with a footing and foundation. Minimum dimensions for a single flue chimney are 16” x 20”.  There is a minimum of 2”  clearance from the chimney to combustible framing.  For aesthetic reasons, a masonry chimney is recommended in new construction when more than one flue is required.  If there will be a ceiling above the heater, the masonry chimney can transition above the ceiling to a metal chimney to reduce costs.

Factory built or “Metal” chimneys:

Metal chimneys are a UL listed product, made to safely vent solid fuel burning appliances when installed according to the manufacturer, right out of the box.  Because the inner flue wall is light weight and able to quickly heat up, they provide efficient venting characteristics.

A metal chimney allows the masonry heater to vent out the top of the unit.  This is helpful when space is a consideration.

Also because there is no footing, foundation or separate, adjacent chimney, there are significant cost benefits.

It should also be noted that unlike masonry chimneys, metal chimneys can offset around floor and roof framing, making them easily retrofitted in existing houses.   And because metal chimneys are a UL listed product, there is stainless steel insulated factory-built chimneys are less expensive than masonry chimneys but offer unique benefits:

Stainless steel chimneys are tested to severe test standards that are impossible to pass for clay flue liners;

Great flexibility. Factory-built chimney manufacturers typically allow up to 2 offsets 15o to 45o to the vertical. This helps to vent heaters in tight situations bypassing combustible framing members and engineered trusses.

For aesthetic reasons, such factory-built chimneys can be enclosed in a framed decorative chimney chase on the roof, finished with number of available light-weight materials to create look of a traditional solid masonry chimney. Factory-built chimneys must to be enclosed inside living space in a chimney chase. Proper clearances specified by the chimney manufacturer have to be observed.

Avoid using exterior chimneys whenever possible. Exterior chimneys create increasing risk of creosote formation and chimney fire, pose condensation problem, and affect draft adversely. Exterior masonry chimneys suffer from deterioration related to condensation of the exhaust gases in the cold chimney flues, and from exposure to inclement weather.


Clearances to combustibles for masonry heaters listed in the ASTM 1602-03 must be considered for proper integration of the heater in to the building. Requirements of the Fireplace Section of a local Building Code should also be observed and followed.

ASTM 1602-03 requires masonry heaters to have following clearances to combustibles:

4” clearance from walls;

8” clearance from ceiling;

48” in front of the fuel loading door;

Non-combustible hearth extension to be minimum 20” in front of the loading door and continue minimum 12” past sides of the loading door;

2” clearance to combustibles from foundation of a masonry heater. It is allowed to cross this gap between floor joists and foundation with sub floor and flooring materials (sample picture below).

If it is desirable to continue facing walls to the ceiling, top of the heater’s core must be insulated, and the enclosed cavity should have means to facilitate air movement to avoid possible static heat buildup.

Refer to the ASTM 1602-03 standard for detailed description of rules and clearances for masonry heater construction.
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