Structural RMH for new Build

So I want to build a house here on our farm for our disabled son (now 18).  I'm after designing a traditional Bulgarian house that  is stone (or brick) on the ground floor and timber framed upper floor which is nearly always plaster rendering.  Total square footage of the little house would be at or under 1000 sqft.  

I would like to make one of the walls (North?) a RMH that is built right into the wall.  Bonus if I can approximate the look of a traditional Bulgarian fireplace.  How would that wall be designed?  How do I size the heater to heat the whole space (upstairs and down).  Winters here in central Massachusetts can get pretty bitter along about January/February.

Anyone want to come and lend a hand? :)

Thanks heaps,

Nissa

I love that traditional look. Do you have a huge amount of stone available for building? You would be surprised at how much it takes if you haven't done it before.

The first thing I would say about building an RMH into an exterior stone wall is Don't. You would be trying to heat the outdoors. Now if the stone wall is double wythe or insulated in the middle so the warmed stones will not transmit directly outside, that could be fine. In general, any stone structure that you want to heat in the northeast climate needs to have the exterior stone face isolated from the interior of the space. I would have loved to build my house with some exposed structural stone walls, and have a large creek with practically unlimited good building stone, but was put off by the choice between a hard-to-heat house and building the wall twice, once for inside and once for outside.

As to the RMH specifically, you can easily replicate the general look of that Bulgarian fireplace with a rocket core in a masonry bell. Specifics will depend on your exact plans, but it will not be hard to make it heat the whole house with appropriate design decisions.

I would consider the nature of your son's disability in deciding on the size and configuration of the house. Will he have any difficulty navigating a two-story layout? (I would presume not, or you wouldn't have suggested it in the first place.) How much difficulty will cleaning and maintaining a house be? Would it be better to make it smaller to reduce the effort required? Would the simplicity of feeding a J-tube be better than the greater complexity and batch capacity of a batch box?

Seconded about not using an external wall - you'll end up heating the outdoors. What about using it as the structure for an internal central staircase, to access the upper floor?

We produce more stones than food here on the farm.  Sad, but true.  Stones shouldn't be a problem at all.  AND, we may have the option of a whole lotta bricks.  The old woolen factory in the village is being demolished and I've already asked for as many as they want to dispose of.  Our farm was owned by the same guy that owned the mill, so that's nice. Bonus: our neighbour and good friend is a stone mason.  I haven't spoken with him because I don't want him to get the impression that we only love him because he's handy.

I figured it would need to be a double wall with insulation in it.  I guess I wonder what to put into that space - traditional insulation materials whether fibreglass or something like wool, old jeans, or should I be using gravel, soil, sand, vermiculite or...?  

My dad built a reproduction of an antique home.  His heat comes from the huge centre fireplace and vents open between floors (no ducts).

My son's disability isn't physical and he's not medically fragile, but he does need to live with a family member or aide to help him with activities of daily life.  Cleaning isn't a worry for him - we don't call him Neat Nick for nothing.  Stairs aren't a problem.  The space will give us a way for family to sometimes gather with him there, and for artworks to be made.  

Thanks so much for responding!

Nissa

Glenn Herbert wrote:I love that traditional look. Do you have a huge amount of stone available for building? You would be surprised at how much it takes if you haven't done it before.

The first thing I would say about building an RMH into an exterior stone wall is Don't. You would be trying to heat the outdoors. Now if the stone wall is double wythe or insulated in the middle so the warmed stones will not transmit directly outside, that could be fine. In general, any stone structure that you want to heat in the northeast climate needs to have the exterior stone face isolated from the interior of the space. I would have loved to build my house with some exposed structural stone walls, and have a large creek with practically unlimited good building stone, but was put off by the choice between a hard-to-heat house and building the wall twice, once for inside and once for outside.

As to the RMH specifically, you can easily replicate the general look of that Bulgarian fireplace with a rocket core in a masonry bell. Specifics will depend on your exact plans, but it will not be hard to make it heat the whole house with appropriate design decisions.

I would consider the nature of your son's disability in deciding on the size and configuration of the house. Will he have any difficulty navigating a two-story layout? (I would presume not, or you wouldn't have suggested it in the first place.) How much difficulty will cleaning and maintaining a house be? Would it be better to make it smaller to reduce the effort required? Would the simplicity of feeding a J-tube be better than the greater complexity and batch capacity of a batch box?

Hi Michael,

I figured that I'd need to plan on a double wall on that side.  Any thoughts on what to fill in with?  

Really cool staircase idea, too!

Nissa

Michael Cox wrote:Seconded about not using an external wall - you'll end up heating the outdoors. What about using it as the structure for an internal central staircase, to access the upper floor?

Great idea, Nissa! You probably already know that the Bulgarian houses use a lot of wattle and daub in the upper storey, especially for internal walls. Light strawclay is used a lot for insulation on floors and ceilings. Not sure about walls.

What a great idea, I hope you send images of the progress.
How long will it take to build?

Yep.  Light straw clay sounds perfect as an alternative.   Now I'll be down a rabbit hole to see all of the possible iterations of light straw clay-like materials and applications.  Lots to think about as I go along.  Like roofing material.  I love these clay tiles.  Nowadays they use more of the rounded clay tiles laid out in the 'priests and nuns' configuration.  I've also seen slate (or slate-like) roofs.  I'm not sure how those are held in place.  They look a bit higgledy-piggledy, as though someone has just tossed them up there to be held by nothing more than sheer bloody mindedness. :)  Surely not.  There must be something holding them on.  But then, it is Bulgaria.  It surprises me all the time.

Nissa

Jane Mulberry wrote:Great idea, Nissa! You probably already know that the Bulgarian houses use a lot of wattle and daub in the upper storey, especially for internal walls. Light strawclay is used a lot for insulation on floors and ceilings. Not sure about walls.

Probably forever. :)  I've no idea.  It will all depend upon the help I can get.  I hope that we can have something at least all closed in and somewhat livable a year from now.  He's away having treatment and that will take many months.  I intend to use the time wisely.

Nissa

John C Daley wrote:What a great idea, I hope you send images of the progress.
How long will it take to build?

LOL, I believe the flat stone roofs, like the one in your picture, do stay where they are by a combination of their weight and frequent maintenance by the residents. I still love them and dream of living in a house with those, but they're typically only found in the mountains where the rock can be split into flat sheets like that.

The house i'm in the process of buying is a long way from the mountains, more modern, probably mid-20th C, and has the clay demi-lune tiles. LOL, and a large assortment of bits of flat scrap metal where they've slipped!

I'm putting together a project in Silistra Oblast.  Also a long way from the mountains. :)  Most of the dwellings there are more modern and have the curved tiles and assorted patches made from whatever could be found. :)

I love it there.  

Jane Mulberry wrote:LOL, I believe the flat stone roofs, like the one in your picture, do stay where they are by a combination of their weight and frequent maintenance by the residents. I still love them and dream of living in a house with those, but they're typically only found in the mountains where the rock can be split into flat sheets like that.

The house i'm in the process of buying is a long way from the mountains, more modern, probably mid-20th C, and has the clay demi-lune tiles. LOL, and a large assortment of bits of flat scrap metal where they've slipped!

LOL, yes! My little house is right next door in the northern part of Dobrich province. The roof is equal parts old bits of flat metal and curved tiles, with a few modern flat tiles thrown in.  I'm considering reroofing it in metal roofing, which works well in Australia where I grew up. Just a little concerned about the wind lifting metal sheets, so we shall see.  The scrap metal sheets seem to stay in place okay, so it might work, with good roof ventilation to vent the hot air in summer.

I hope to get some time to work on it next year. Between Brexit and Covid and my husband being less well, I haven't been able to get out to Bulgaria for some time.

Praying your project and the build for your son both go well!

Total square footage is around 1000sqft,
Uninsulated "Basement" made of Stone/Brick
Upper Living Area made of Earth Plaster/Cob/Strawbale, with timber supporting the roof and R-30 insulation of strawbale/cellulose/foam/rockwool

Total square footage is around 1000sqft, is this just for the upper living area? Or do you see it as 500sqft for the "basement/workshop" + another 500sqft for the upper living area?
What do you think of this 1000sqft upper living area floor plan?


HVAC
Heating: in floor radiant heating ($1000 for 1000ft of PEX pipe + $250 pump + $1000 water heater-wood boiler/pellet stove/gas/heatpump)
Ventilation: $1000 ERV, fresh air intake, vents humid bath, filters air (indoor&intake)
AC: $1000 Dehumidifier and or optional mini-split

Roof: I recommend 4ft overhangs to protect the earthen roof. esp after the 6inch of rain we just got and 60mph wind.
Stonewall "Basement": if you were to add insulation to this area would it be on the inside or outside, what would we cover the insulation with (drywall/plastic siding)
Laundry:
Bathroom: Will it be compostin
Kitchen: How can we optimize this design, I assume there will not be alot of food preservation, how about outdoor kitchen?
Ease of Repair/Maintain: How easy will it be to repair/maintain the HVAC, roof, etc as the laws change and we age
Ease of Use: I recommend 3ft doors so that it is easy for furniture, wheelchair and mobility, as we all age in place. Should we really have 2 stories? Where will we place the live-in quarters, will it have its own bathroom how about kitchenette? What design choices will you can you make now to give you the most adaptable house for future situation as we age/etc? RMH system needs to be redone every 5yrs, and finding skill labor is hard.

Fireplace and esp RMH are usually put in the center of a house so that it can heat things to front and back of it. RMH also need to be replace every 5yrs or so, some folks have to redo it every 3yrs maybe a few folks can spend a ton of money and make it last 7yrs

My experience is that if the right design choices are made and materials used, an RMH can last far more than five years. Mine is five years old now and still probably decades away from any serious maintenance required, let alone rebuilding. It will need some minor things like repairing the P-channel soon. I did spend a few hundred dollars up front on things like a welded steel feed tube liner and P-channel, steel access panel in the bell, and heavy duty firebricks. Most of the material was scrounged or taken from my land, though.

I think the short-term rebuilding stories come from people who didn't fully understand the process in their first build, or couldn't get good enough materials, or have decided to upgrade to a different core or mass system.