Brick Floor - can it work?

I am planning construction of a 200 sq ft cottage, and I am fascinated by the idea of using bricks as the flooring.

We are building in the moist Pacific Northwest, and the site slopes down to the north; the southern end of the structure would be just above soil level but at 20' away the northern end will rest on piers approximately 2.5' above the soil. This should allow for good air flow under the structure. I've been told pier blocks buried just until the top of the concrete is almost covered is the best kind of foundation for my 10' x 20' footprint. Then we will run 4"x4" lumber in the metal channels embedded into the concrete blocks, and use metal Simpson ties to attach the 2"x4" wooden joists.

As much as I'd like to avoid plywood, I haven't been able to figure out another kind of sub floor material. I imagine I could use old wool carpet, or denim insulation, or a layer of wool, as a thermal break on top of the plywood, and then simply lay down bricks as tightly as I can manage, without sand in between. In my mind, this should work as mass to be heated by a Matt Walker-style tiny house cook stove and heater. The area where the stove will sit will be reinforced by more blocks under the joists to handle the brick load - but I wonder what spacing I should use on the rest of the joists to make sure they can handle the brick floor weight?

My hope is that I will have a "breathable" floor that will be cool to the feet in the summer, but can be warmed by the stove in the cooler months. The heat from the stove could also keep the bricks dry in our wet winters. I am hoping to use the ideas I will be trying in this little cottage as a test run for natural methods to build a larger structure in the next few years. The walls will be "palletable cobbins" - pallets stuffed with clay straw slip - and I'm still trying to decide if I want to use a natural plaster finish on the outside of the pallets, or figure out a way to attach cedar shingles - because I love the look of it - and we have a little cedar shingle miller in the neighborhood.

Can this idea work the way I imagine? Thanks in advance for all your great feedback!

Which weighs more? A cubic foot of aluminum, or a cubic foot of granite?

Neither...they both weigh the same. Kind of surprising huh?

The reason I answered like this is because I ran into the same sorrt of question when I did some concrete countertops in my house. Surely I needed to reinforce the cabinets to support the extra weight! NOPE. While concrete is inheriently heavy at around 3000 pounds per cubic yard, at 2 inches thick, spread out over a broad surface, my countertop would only be 12 pounds per cubic foot. That is feather light.

I think you might be in the same situation, while brick is heavy, because you are spreading the weight out over a broad surface, with only a little modification, a standard floor should be able to handle the load. It is easily calculatable in any case, just take the weight of a standard brick (5 pounds) and calculate it by how many bricks it would take to make a square foot of area. (7). In this case you are looking at only an extra 35 pounds per square foot.

To strengthen the flooring you have two options, both fairly cheap.

1: Since the strength of a beam goes up drastically by its depth, instead of using...say...2x8's as floor stringers, use 2 x 10's, or 2 x 12's
2. or you could just space 2x8 floor stringers closer together, say...12 inches on center instead of 16 inches on center.

A third option would be to go with both options so you have a super strong floor; space 2x10's 12 inches on center.

We do not have a brick floor, but we do have a slate floor and love it. Ours is only in our entry area, but because it has radiant heat on it, it is warm in the winter. Without the heat running, it is cool in the summer. We love it, but not as much as our cat!

Oh, one bad thing about stone or brick floors, they are VERY hard on dinnerware. If you fumble a plate, its a goner, no bouncing like you sometimes get off a wooden floor.

Thank you, Travis. Great help in your answers!

In our current enclosed single-wide, we have 12" natural clay tiles in the entry/dining/kitchen area, and we love them. Since neither of us can tolerate heat very well, we love how cool they stay in the summer. I was hoping to avoid grout, and hoping to keep the air exchange capacity up, by simply dry-laying the bricks over a thermal break, and then setting the mass heater directly on the bricks - to warm them up as needed in the cooler months.

And yes, nothing more shocking than the many, many pieces of things that break on a very hard floor - hopefully, area rugs might help...

I love the idea. One thing came to mind, though.

Tudor-era brewmeisters, as well as others who needed cool workshops, would have brick floors with exceptional ventilation. When cooling was required, they'd pour water on the floor, and the evaporation forced by the ventilation would cool the brick, and the room.

This might work well for you, if your design is breathable enough to dry out completely from a good soaking. If, however, you have damp winters that cause your floor to trap moisture, having that evaporate will cool the space further. This might at least work against any heating efforts.

-CK

Thanks, Chris!

Your observations certainly speak to the benefit of being able to heat the floor itself. I just wonder if the bricks under the stove will get hotter than the insulation or sub floor could stand...perhaps those should be firebrick, with the rest of the floor as regular clay brick...

Laura Sweany wrote:Thanks, Chris!

Your observations certainly speak to the benefit of being able to heat the floor itself. I just wonder if the bricks under the stove will get hotter than the insulation or sub floor could stand...perhaps those should be firebrick, with the rest of the floor as regular clay brick...

I am not sure. Fire brick is very brittle so it would easily break???

Laura Sweany wrote:Thanks, Chris!

Your observations certainly speak to the benefit of being able to heat the floor itself. I just wonder if the bricks under the stove will get hotter than the insulation or sub floor could stand...perhaps those should be firebrick, with the rest of the floor as regular clay brick...

Sometimes I don't think quick enough.


One thing you could do that would prevent the problem with heat is doing what they did on wooden ships back in the day; put down some sand on the wooden deck whenever they had their fires to stay warm in the Northern Latitudes. Sand is really resistant to heat. I have done this in my house, but for radiant heat purposes.

Travis, where do you envision putting the sand? Under the stove area?

My problem with sand is that I am wanting to transfer SOME heat to the floor bricks through contact with the stove itself - not just transfer it to the bricks through the ambient room heat. Most RMH units have sand under the stove as a thermal break, since it does not conduct heat well (as you said in your comment)

I could certainly see putting sand under the hottest areas of the stove, then perhaps firebrick laid without any sand or mortar for the bottom edge of the stove, and that would contact the regular red clay bricks, which are also laid without any mortar or sand - so the heat transfers easily from one brick to the next.

Now I wonder if the sand should also be used as the insulation material above the subfloor but below the bricks. Or would that wick away too much heat from the warm bricks?

I think a brick floor would look great in addition to holding the temps you want it to have in the different seasons.

One think I want to mention, after years of working on very hard floors, is that it can be really hard on your feet after a while, expecially if you like to go barefoot. If you wear shoes or supportive sandals, you probably won't have any problem. Just something to think about.

In Tudor times in England, the dairy had porous floor tiles or bricks on the floor. In summer wetting the floor caused the room temperature to come down.
Brick floors are very practical.

We had paving bricks for a floor many years ago in a previous house we built. We eventually laid ceramic tile over it as the bricks were impossible to keep clean. The surface was too uneven to sweep easily. Maybe a vacuum cleaner would have done a better job.  Furniture was hard to place without wobbling. The paving bricks were free for the hauling from an old street in town that was being torn out to make way for resurfacing and worked well as thermal mass. I think regular building bricks would be too soft for flooring. In our "new" home (20 years old) we put down quarry tile, another fired clay product but much more suited to being a floor - easy to sweep and looks great too.

Laura, you might use a double layer under the stove, pavers are easier to clean than regular brick, they can be found thinner that regular brick too.
Most of the time the most heat is around the back sides of a wood stove the floor part of the surround is more for ash/ember fall out I think.
Another option might be to use concrete board under the brick work.

Laura Sweany wrote:Travis, where do you envision putting the sand? Under the stove area?

I am not really sure to be honest with you because I do not have much experience with a rocket mass heater.

In my house, I have radiant floor heat, but had a problem. Half the house had the radiant floor heating tubes embedded in the concrete, but the other half, built in 1994, did not. We love radiant floor heat, so we wanted to add radiant floor heat to the old part of the house though. So for us, we laid the pex over the existing concrete floor and then put sand around the pex tubes, and finally laid wooden flooring over the pex. That has really worked well.

You could use a rocket mass heater to heat a water tank and do the same thing over a wood subfloor. Those pex pipes would heat your sand and then your brick flooring.

Our house is a shoeless house so I have difficulty in envisioning wearing shoes inside, but that is honestly just us (Family of 6), I have NOTHING against those that wear shoes that is for sure. Around our slate flooring we use mortar painted with white paint so that it does not produce dust, and we like that. We do not find the slate to be hard on our feet, but others might disagree. I think to make your brick floors easier to live on, you might want to mortar between the bricks, but then seal the bricks with a sealant. I hate to bring up clear epoxy or polyurethane, but it would be a lot easier to sweep and mop, and yet give you that thermal mass being brick.

Brick's hard surface makes it easy to clean—with a quick sweep or vacuuming—and it doesn't harbor dust and other allergens like carpet. Because brick is noncombustible, it's a good choice for flooring under or near woodstoves and fireplaces, where brick is traditionally right at home