replacing plaster & plaster wall with cement board

[rll111]

I've just learned that I need to tear out the wall where I'm planning to place my woodstove in order to build a brick wall patch around the clay thimble to the brand new masonry chimney. Can I just replace the whole plaster wall section to the floor with cement board so that I don't need to worry about clearances and wall shields? My house is built of stucco & block, with post and beam studs, then plaster lath and plaster. Thanks.

 

[begreen]

Be sure the stove manual permits a reduction for an NFPA wall shield first. What stove is this for? How much of a clearance reduction are you trying to achieve?

If there's wood behind the plaster lath, it's still the combustible that one measures to after the lath is removed. Switching to cement board will not change clearances to the studs behind it unless it meets wall shield requirements. A wall shield requires a - ventilated - 1" gap behind it. It can be built in but will require shimming the cement board 1" off the studs with a non-combustible material. full length, 3" strips of the cement board work well for this. And the built in shield will need to be open at the top and bottom to allow air to easily pass behind it. However, you may not need the max reduction of a full wall shield. There may already be enough of a reduction if this is a full-size brick wall.

 

[Jags]

As BG was getting into - you are still gonna need to pay attention to clearance to combustibles if you have wood studs. To answer your question on replacing the old P & L - you could replace it with cement board and then skim coat it, though typically it is done with blue board (kal kote) and then the board is finished with a base and finish coat.

Cement board does not eliminate the C-To-C requirements. It may reduce them, but thats not guaranteed either. Follow your manual.

 

[rll111]

OK, thanks for your help. Now another question. The stove I have is an older Vermont Castings Vigilant, a coal/woodstove. I know now that it's not the most PC stove, but it's what I can afford right now. I'm going to be burning all the dead oak trees on my property. They're dying of sudden oak death - I might as well get the BTUs out of them. My question is - do I need to keep all the coal shaker pieces inside the stove, or do I just use the ash pan by itself.

 

[Jags]

I can't say what parts can stay and go for your stove, but I do know that combo coal/wood stoves usually make poor and inefficient wood stoves. It has to do with the way the air routes for coal vs wood. If that is what your stuck with, so be it, but be aware that you are gonna be feeding that stove like shoveling rice off of a container ship.

Keep an eye on your stack. Its not gonna burn that wood real clean either. Try and keep the temps up when you are running it, no smoldering.

 

[johnn]

Quote:" by various laboratories around the country show that as wood burns, 80% of it burns in the gaseous state while 20% burns as fixed carbon in the solid state. Coal burns just the opposite of wood, that is 80% burns as fixed carbon and 20% burns in the gaseous state." Jags is pointing out that your supply air for combustion, may be centered on the solid wood causing it to burn rapidly>

 

[johnn]

Quote:" by various laboratories around the country show that as wood burns, 80% of it burns in the gaseous state while 20% burns as fixed carbon in the solid state. Coal burns just the opposite of wood, that is 80% burns as fixed carbon and 20% burns in the gaseous state." Jags is pointing out that your supply air for combustion, may be centered on the solid wood causing it to burn rapidly>

wow! ive read 50-60% for woodgas. from montana st. u.

Dunno CZARCAR: Thats off "Woodchuck wood and Coal Furnace" literature, They have an 80/20 Combustion Air Selector mechanism. I guess this MAY only apply when you bring Secondary Combustion into the scenario. Just guessing.