Simple easy light hearth help

[Foopysfarm]

I am building a small 10x16 cabin. I've never built anything before and I'm just finishing up the outside. I'm planning to install lvp flooring. For the space where I'm planning to put the free standing wood stove I need help designing the flooring/hearth underneath. I want simple, easy, and light. The joists supporting the floor are getting close to pushing their luck in terms of span.

I don't have a stove picked out yet (need help with that too but probably for another thread) so I don't know the manufacturers requirements.
My initial thoughts after doing some reading on this thread is an additional layer of 3/4 plywood with a 1/2 cement board and then a store bought stove board on top. Does this make sense?

How do I attach the cement board to the plywood? And the stove board to the cement board?

I'm thinking something like this: https://www.northlineexpress.com/32-x-42-ul-1618-black-stoveboard-t2ul3242bl-1c-2447.html

 

[KDubU]

There are specific types of screws to use with cement board as regular ones can break down (see pic). The 3/4” ply will give you added strength definitely and am assuming due tot he size of the cabin, you will go with a small stove (less weight than large stoves).

Make sure the hearth you’re building is large enough for the stove as there are setbacks for each stove.

 

[Ashful]

How did you select your joist sizing and spacing for this span? Placing a 500 - 700 lb. dead load on a questionable span can be a lot worse than feeling a little spring in your step due to high live loads, so you may want to give some attention to this, before moving a stove into that space.

As to the floor covering, there are enough stoves now that require "ember only" protection, that I wouldn't be super concerned about floor R-value. Cover the area around the stove and a generous margin around it (eg. 24" all sides) with tile, stone, or metal, and then choose one of the many stoves only requiring ember protection.

 

[begreen]

If the floor can't support 2-3 adults standing in that location, it needs help.

Picking out a stove that requires ember protection only will simplify things. To reduce weight, an ember protection only hearth can be just sheet metal (steel, stainless, etc.). For a cabin of that size there are several stoves in the ~300# range that will work.

If you want a tiled hearth, then your plan is fine.

 

[Foopysfarm]

How did you select your joist sizing and spacing for this span? Placing a 500 - 700 lb. dead load on a questionable span can be a lot worse than feeling a little spring in your step due to high live loads, so you may want to give some attention to this, before moving a stove into that space.

As to the floor covering, there are enough stoves now that require "ember only" protection, that I wouldn't be super concerned about floor R-value. Cover the area around the stove and a generous margin around it (eg. 24" all sides) with tile, stone, or metal, and then choose one of the many stoves only requiring ember protection.

I kind of just winged it. I am spanning about 10 feet between my beams and doing so with 2x10s 16 OC.

If a stove requires ember only protection does that mean I can use one of those pre made store bought stove boards? How do those secure to the cement board?

 

[Foopysfarm]

If the floor can't support 2-3 adults standing in that location, it needs help.

Picking out a stove that requires ember protection only will simplify things. To reduce weight, an ember protection only hearth can be just sheet metal (steel, stainless, etc.). For a cabin of that size there are several stoves in the ~300# range that will work.

If you want a tiled hearth, then your plan is fine.

Any direction on where to find plans for a simple tiled hearth? Or is the idea for ember only protection any tile material is fine and it's more about the setback and spacing? I initially wanted to do brick for the aesthetic but because of weight and time to build the heath I am passing. I'm hoping I can find something that can be built or bought in a half day.

 

[Foopysfarm]

If the floor can't support 2-3 adults standing in that location, it needs help.

Picking out a stove that requires ember protection only will simplify things. To reduce weight, an ember protection only hearth can be just sheet metal (steel, stainless, etc.). For a cabin of that size there are several stoves in the ~300# range that will work.

If you want a tiled hearth, then your plan is fine.

Regarding help picking out a stove should that be a new thread? Catalytic vs not? Through wall of roof? Size? Etc?

I'm trying to self research but it's a rabbit hole. Main goal and requirements would be bigger logs and longest burn time possible while keeping weight and cost down. I'm a noob so I want something safe and easy to use that I'm not having to process a ton of firewood for and constantly feed.

 

[begreen]

I kind of just winged it. I am spanning about 10 feet between my beams and doing so with 2x10s 16 OC.

It will be fine. We have a 600# stove an hearth sitting on full dimension 2x8s, 24" OC, 36' span. It's not recommended, but in our old farmer-built house, that's what's here. When we raised the house we added several beam supports at 10' intervals underneath in the crawlspace

 

[begreen]

An ember protection only stove will just need a solid barrier that prevents a hot coal falling on the hearth from causing fire. It can be a sheet of metal, heavy glass, grouted tile, half-thick brick, etc. The stove's installation instructions will define the minimum size for the hearth. It's fine to go larger and recommended if there's room.

Regarding help picking out a stove should that be a new thread? Catalytic vs not? Through wall of roof? Size? Etc?

I'm trying to self research but it's a rabbit hole. Main goal and requirements would be bigger logs and longest burn time possible while keeping weight and cost down. I'm a noob so I want something safe and easy to use that I'm not having to process a ton of firewood for and constantly feed.

I suggest not worrying about log length as long as it's over 16". North/South loading will prove more important parameter to utilize the full capacity of the firebox. Going straight up through the roof for the flue system is always preferable and often less expensive.

First thing, establish a budget for the whole installation. Then start reading past threads for new stove advice. There are at least a dozen a month.

 

[Ashful]

I kind of just winged it. I am spanning about 10 feet between my beams and doing so with 2x10s 16 OC.

I agree with begreen, that setup should be sufficient. But you mentioned issues with weight and floor deflection?

 

[NHWS]

An ember-protection-only stove with enough 3/4" plywood to handle the weight plus a metal hearth pad might be the easiest. For any kind of tile or brick hearth pad (pre-made or made in place), vertical deflection is a major issue. In that case, reinforce the floor with additional joists or at least several layers of plywood. Cement board is commonly used above the plywood, but a self-leveling compound with a paint-on isolation membrane would be simple to apply and would ensure that the floor below the tile/brick was very flat.

 

[begreen]

An ember-protection-only stove with enough 3/4" plywood to handle the weight plus a metal hearth pad might be the easiest. For any kind of tile or brick hearth pad (pre-made or made in place), vertical deflection is a major issue. In that case, reinforce the floor with additional joists or at least several layers of plywood. Cement board is commonly used above the plywood, but a self-leveling compound with a paint-on isolation membrane would be simple to apply and would ensure that the floor below the tile/brick was very flat.

It's really not necessary. I should also note that we have a heavy tile hearth under our heavy 3 cu ft stove. This installation will be for a stove half the weight on a decent floor substructure.

 

[Foopysfarm]

I agree with begreen, that setup should be sufficient. But you mentioned issues with weight and floor deflection?

I kind of just willy nilly designed the plans in sketch up with limited knowledge and doing my own research. Other engineering/architecture forums are the ones who have me worried I'm pressing my luck on span/joist size. No real world issues yet.

 

[begreen]

If it helps, I can not recall in the 18 years here where this has been posted as an issue. That isn't to say it hasn't happened, but I don't think anyone has reported this as a problem in their house.

 

[Foopysfarm]

Reading other threads on small cabins I'm quickly being persuaded wood heat might not be the right fit because my space is too small but I really want it from a environment/feel/aesthetic perspective. It seems like with my small floor space minimizing hearth space is going to be my biggest consideration so it doesn't take up the room. Wondering what the minimum realistic possible is for floor space. I'm going to start a new thread.

 

[begreen]

You are correct. Unless the cabin is high up in the Cascades it's not going to take a lot of heat to keep it warm. Our greenhouse is bigger than the cabin. Are the walls and ceiling insulated? Does it have power?

Read up on the several tiny home threads. There are some stoves mentioned in those threads that might work out for you. Here's one to start:

Tiny wood stoves for tiny houses

This topic comes up often so I thought I would start a thread that contains links for stoves for small spaces. This Canadian site has some nice models made by Ekol and others. Some are quite stylish. They also have chimney supplies which can be hard to find for small stoves that have a 4" flue...

www.hearth.com

 

[Foopysfarm]

I haven't insulated the walls or ceiling yet but was planning to for the summers. I'm at 2400 ft elevation and it gets below freezing but not MT cold. A wood stove has always been an integral part of my vision so I'm super bummed to be learning this but if it doesn't make sense, it doesn't.

 

[Foopysfarm]

You are correct. Unless the cabin is high up in the Cascades it's not going to take a lot of heat to keep it warm. Our greenhouse is bigger than the cabin. Are the walls and ceiling insulated? Does it have power?

Read up on the several tiny home threads. There are some stoves mentioned in those threads that might work out for you. Here's one to start:

Tiny wood stoves for tiny houses

This topic comes up often so I thought I would start a thread that contains links for stoves for small spaces. This Canadian site has some nice models made by Ekol and others. Some are quite stylish. They also have chimney supplies which can be hard to find for small stoves that have a 4" flue...

www.hearth.com

I'm very intrigued by the dwarf 4k from tiny wood stoves in Idaho. Unfortunately don't see any info on this site regarding review. Thanks so much for your help

 

[Foopysfarm]

If I were to go with a 100# ember only protection stove I could probably put this right on my lvp with layer of ember protection and no extra need for plywood or special flooring build up?

 

[begreen]

Perhaps. It depends on the stove. I'm not sure if the tiny stoves are ember protection only.

 

[NHWS]

Even if the stove only requires ember protection, installing directly over lvp may not be a good idea. The floor may still reach 100 to 110 degrees F. Vinyl planks will handle that temperature for a while, but they will soften over time, particularly when there is a constant weight on them. Shaw floors has had problems with vinyl planks under furniture in the U.S. southwest, and they have started rejecting warranty claims for lvp under or near wood stoves.

A layer or two of 3/4" plywood would probably be worth the effort.