Installing A Pellet Stove

So you're thinking about installing a pellet stove. You probably know the area you want to put it in, but now there are some factors that have to be planned exactly.

Firstly, is the floor strong enough to take the weight? Pellet stoves can be heavy, particularly the cast iron models. It's not likely that the stove will fall through the floor unless the floor structure is seriously deteriorated, but significant weight in a small area can distort a wooden floor over time.

One way of spreading the weight out without strengthening the floor itself is to install a pellet stove on an extra large hearth pad that has some load bearing capacity. A large piece of natural stone or a cast cement pad could be used for this purpose but those materials are heavy themselves.

A lighter load bearing pad can be built on a timber frame, (2" by 4") aligned so that it crosses the joists under the flooring at right angles. This can then be covered with three quarter inch ply and tiled.

Planning The Venting

If you are planning to vent through the wall you need to know where the wall framing timbers are located. If planning to vent through the ceiling you need to know where the flooring joists are. When you look at the short video below, you will see that the vent pipe is not vertical. This is probably because the hearth pad has been built without considering the wall framing.

Installing A Pellet Stove: Short Video

Consult the stove manual or measure the pellet stove to find out exactly where the exhaust vent outlet is located. It is likely that it's not on the centre line of the stove.

Allowance must be given for the size of the wall thimble or the ceiling firestop spacer. Locate the timbers with a stud detector, drill small holes to check, and then drop a plumb line down from where you want the centre of the wall thimble or firestop spacer to be and align the stove vent outlet to that.

Installing A Pellet Stove: Windows And Doors

The rule is that a pellet stove must not terminate within four feet to the side or below opening windows or doors. This can be reduced to 18 inches if the stove uses an external air source for combustion. Above windows and doors the clearance is reduced to twelve inches, nine inches with an outside air supply.

The reason for this is to prevent exhaust gases from the stove being sucked back into the home. An outside air supply reduces negative pressure in the home which might bring back vent gases through a window or door opening.

It is possible to place a pellet stove underneath a window. The pipe should be run at an upward angle below and past the side of the window, then continue vertically up to a suitable termination point.

Installing A Pellet Stove: Clearance To Combustibles

Combustibles in this case means wall and ceiling structure as well as furnishings within the home. Your pellet stove manual will give minimum clearances to combustibles which it is always better to exceed if possible.

Some pellet stoves have optional heat shields which can reduce these clearances.

Installing A Pellet Stove: Moving Into Position

As you saw in the video above, pellet stoves can be heavy, (that's a cast iron stove in the video). The little truck they have for taking the stove up steps is great, but I wouldn't want to use that on a staircase without a fail-safe rope system in place and someone to take up the tension as it moves upwards.

Inside the home, a bunch of strong willing arms helps a lot. To avoid back troubles, rope a beam of wood to the top of the stove. This will allow the lifters to stay upright and clear of sharp metal edges.

Sliding the unit around on a strong plywood pad works well on a flat surface and avoids damage to the flooring and hearth.

Finally, always check your stove manual and building codes, making sure that you comply with both.