Heat Shield Construction Rules Minimum clearance along the top of shield at ceiling: 75 mm (3 in.). Shield extension beyond each side of appliance: 450 mm (18 in.). Shield extension above appliance: 500 mm (20 in.). Edge clearance for ceiling shields: 75 mm (3 in.).
Minimum space between shield and combustibles: 21 mm (7/8 in.). Minimum clearance along the bottom of shield: 25 mm (1 in.). Maximum clearance along the bottom of shield: 75 mm (3 in.). Minimum clearance along the top of shield at ceiling: 75 mm (3 in.).
If you are using a heat shield to reduce clearances in a project subject to building codes, the shield cannot reduce clearances from the appliance to the wall less than 12" with an air-cooled shield or less than 18" with an insulated shield unless the shield and stove are specifically tested and listed for that purpose ...
It must be affixed to the wall using non-combustible fixings, with an air gap of at least 25mm between the heat shield and the wall. The heat shield must be open at both the top and the bottom to allow the flow of cool air between the shield and the wall.
A properly constructed heat shield can be used to safely reduce minimum clearances between walls and wood burning appliance. The shield is required to extend at least 500 mm (20 in.) above the top of the appliance and 450 mm (18 in.) beyond each edge of the appliance.
You must have a non-combustible hearth or flooring that extends at least 18 inches in front of the stove and 8 inches past the sides and back. If any sparks escape the stove or the flooring gets too hot, this clearance can protect against fire.
The industry's solution for heat shields
PermaBASE cement boards are the industry-preferred choice. Installation-ready and easy-to-use, PermaBASE® cement boards eliminate the need for field fabrication, saving time while allowing for enhanced performance and wood-burning stove placement closer to the wall.
At least 36 inches of clearance must be allowed between the top of a stove and an unprotected ceiling.
All stoves in homes built after 2008 require either an air vent or external air intake, regardless of heat output. Without it, the stove may struggle to draw sufficient air for clean, efficient burning. Even in older homes, a stove can benefit from an external air kit.
To reduce the standard clearance to 12 inches, the heat shield should be of 28-gauge sheet metal, mounted off the floor to provide unrestricted circulation of air between shield and wall (see Figure 1). WHAT SIZE HEAT SHIELD DO I NEED? Any area within 36 inches of the wood stove should be covered as shown in Figure 2.
A minimum of 150mm (6”) is required above the stove (500mm if there is a wooden mantle/beam) and 100mm (4”) either side. However, the more space you have around the stove, the more effectively it will heat the room.
Wood stoves require heat shields both under and behind them to protect your home from heat damage. While many wood stoves include heat shields in their design, some do not.
A chimney must extend at least 3 feet above a flat roof and at least 2 feet above a roof ridge or any raised part of a roof within 10 feet. Sometimes getting enough vertical clearance to prevent eddy currents from affecting chimney draft is impossible. This may be because of unusual heights of nearby trees.
Heat Shield Construction Rules
Minimum clearance along the top of shield at ceiling: 75 mm (3 in.). Shield extension beyond each side of appliance: 450 mm (18 in.). Shield extension above appliance: 500 mm (20 in.). Edge clearance for ceiling shields: 75 mm (3 in.).
The good news is that most modern models of Wood Stoves are able to be put closer to walls than earlier models. While older stoves needed as much as 36”, newer stoves can be put as close as 6” to combustible walls with no additional protection needed.
Minimum distance from the top of the stove or single skin flue pipe to the top edge of the heat shield should be 300mm. The overall width of the heat shield should be at least the width of the hearth which should conform to building regulations.
Combustion air supply
In an airtight home, it's incredibly important that a log burner has a proper supply of air. A proper supply of air will not only help the log burner burn properly, but it'll keep things safe too.
Never use PVC pipe, gas vent pipe, dryer vent pipe or single wall black stove pipe to vent your pellet stove.
Building regulations provide exact specifications for determining the minimum size of air vents for wood-burning stoves: The air vent must provide at least 550 square mm of open aperture area per kW of rated heat output from the stove. For example, a 5kW stove would need 550 x 5 = 2750 square mm of open vent area.
Using PermaBASE Cement Board as a wall protector in between the stove and the combustible wall materials allows you to shrink that distance by 40% or down to 14".
Woodburning appliances shall be installed with the following minimum clearances to combustible construction: Above the top of appliance--thirty-six inches; from front--thirty-six inches; from back--thirty-six inches; from sides--thirty-six inches.
The minimum clearance required directly above the location of the cooktop is 750 mm (30 inches) from the level of the cooktop burners or elements to framing, finishes and cabinetry.
Some high-end rigid heat shields are made out of either aluminum, gold or composite, with most examples including a ceramic coating to provide a thermal barrier, which improves heat insulation. The flexible heat shield are normally made from thin aluminum or gold sheeting, most commonly sold either flat or in a roll.
Concrete, like other stone or brick material, is non-combustible and makes an excellent choice for your wood stove or wood-burning fireplace. Your hearth can be flush-in-floor, raised or cantilevered.
Because this often places the stove out into the room, many home owners choose to build a wall shield instead. The most common way of doing this is to tile the wall or a portion of the wall behind the stove.