This is something you can’t put a price to. It is like the credit card advertisement:

Insulation $10

Radiant floor $15

Fiberglass Windows $12

Watching your baby play naked while it snows outside: Priceless

This photo really [...]]]>

Here is a great image. It shows the true value of a Brooklyn brownstone green renovation.

This is something you can’t put a price to. It is like the credit card advertisement:

Insulation $10

Radiant floor $15

Fiberglass Windows $12

Watching your baby play naked while it snows outside: Priceless

This photo really shows the immediate value of doing a good energy efficient renovation of a brownstone. The cost to do it is not more that to do it badly.

You just need to put the money and attention in the right places. The floor is salvaged from a dumpster. The sheet rock and insulation is also salvaged. This allows more money for the radiant floor and Low E fiberglass frame windows.

We insulated the walls like crazy. It has around R 40 with a radiant barrier and air seal. The floors are R35 and the space below them is another apartment so it is warm down there anyway

The windows are good quality. They aren’t triple pane which would be ideal but they are still really good.

The room is not overheated but the heat is in the right place: near the floor. It keeps your feet warm and this moves up your whole body. It is much more effective than a warm room and cold floor. And it is right where my son likes it since he is barely two feet tall!

Another small element are the salvaged marble window sills. They suck up warmth from the sun, which comes through even if it is cloudy, and release it throughout the day and evening.

Warmth from a radiant floor is like no other warmth. A fireplace gives you that scalding on the face and cold back feeling. Forced air is useless. Baseboards don’t do much for the floor where it really matters. Radiant is just right, as Goldilocks would say.

Outside it is snowing and very cold. Inside it is a wonderfully comfortable warm. It is moments like these when I love being a green contractor in Brooklyn because it is so satisfying making these kinds of homes for people. Their quality of life is so drastically better for the same costs. In fact the costs are less once you factor in the life of the home. The heating bills for this kind of home are much less than a normal home.

And this is not theory. We did it in the Brooklyn Green Show House. We do it for clients. It is actually pretty amazing more people don’t do it. But that is changing.

Try as we might we couldn’t figure out why. We tested pump pressure, we made sure we hadn’t crossed pipes somewhere, we [...]]]>

We just had a hell of a time finding a problem in the radiant floor system of the Brooklyn Green Show House. Some of the zones in the house didn’t heat up.

Try as we might we couldn’t figure out why. We tested pump pressure, we made sure we hadn’t crossed pipes somewhere, we tested the thermostats, we calibrated the boiler, we switched the manifolds, we reversed the pipes, we checked the pressure, we checked the heat, we did everything.

We did everything except remember that 99% of radiant floor problems are due to air in the pipes. Sure we purged the pipes of air, or at least we thought. But we hadn’t gotten all of it. So all along the most simple solution was the issue.

And we consider ourselves radiant floor specialists for Brooklyn Brownstones….

Any time a radiant floor system is not working it almost always is due to air being trapped in the pipes. This causes blockage and reduces the pressure which means the water can’t flow and the floors don’t heat up.

Here are useful diagrams for purging radiant piping of air. It is a simple procedure and does not need a $300 visit from your plumber to do.

In both these cases it did not work to put pex tubing OVER the subfloor. So we had to hang it below the [...]]]>

We are installing radiant floor heating with pex tubes. We had a set of challenges:
The floor height was low or the floor already had wood flooring on top of it.

In both these cases it did not work to put pex tubing OVER the subfloor. So we had to hang it below the sub floor. This is not ideal since the heat from the tubes has farther and more to travel through in order to get to the room above. To make up for that you need hotter water temperatures and this costs more money.

The standard way of dealing with under floor pex it to attach aluminum fins to them. This draws out the heat nicely.

I had issues with that route.
1. we had to snake the pex through existing joists so straight aluminum would fit so well with our windy pex.
2. fins are expensive.
3. aluminum has high embodied energy.

So since Eco Brooklyn is all about innovative green technology we decided to challenge industry standards and we set out to find a cheaper, more labor intensive, less embodied energy approach. For me these three elements are key to green building.

Cheap is easy to relate to. Everyone likes cheap provided the quality isn’t. Embodied energy most people can get. It basically means less impact on the environment.

More labor intensive is something people don’t get. But for me it is very important. I have people coming to my doorstep basically begging for work with sad stories of families to feed. Why would I not find a way to employ them? The best way to do this is to reduce my materials cost so I can afford to increase my labor cost.

This means buying cheaper raw materials and assembling them on site with labor.

Doing this is the most powerful way of keeping the money in the community.

So I figured I wanted something that pulled the heat out of the tubes. Cement is cheap (but labor intensive). And it is gotten locally. Pex tubes in a concrete slab work great for example.

Of course attaching cement to the bottom of a floor is not easy. There were considerations:
humidity issues of wet cement
weight issues of dry cement
keeping it attached for over 50 years

We tried many things:
Plywood cement sandwiches that we screwed up
Metal lath like a stucco job
Particle board with holes in it
Wire
Chicken wire
Nylon Mesh

It took a couple days to find a solution.

What we settled on is foam insulation for pipes that are filled with cement and then screwed up to the subfloor around the pex. At first we punctured the foam with holes to let the humidity out but then we found the screw holes were sufficient. NY isn’t humid in the winter. We also started out by wiring it up but found that screwing it was better and more long term since the cement will dry around the screws.

We used external screws that won’t corrode.

The foam had the right amount of rigidity and flexibility. It was naturally rounded to hold the cement. And it had the added benefit of insulating the cement from below. The heat only has one way to go once it is pulled out of the pex: UP. And that is where we want it.

Here is what the final thing looks like:

First we cut the tube and splice it so it lays more flat:

Then we put cement into it:

Then we screw it up around the pex tubing:

Here are some ways we deemed not good because they either didn’t stick to the subfloor or took too long:

Wire lath with cement:

Using wire to hold it up had issues with longevity:

The end result is that we think we found a good solution. Factoring in costs and labor the price of a radiant floor cement installation is cheaper. The work is not complicated and can be done by an unskilled person. It takes about twice or three times as long as installing aluminum.

For small jobs where you are making a green brownstone I think it is a good alternative to aluminum fins. And again, it might make sense for large jobs too if you have time and want to save on materials.

Of course the big question is whether it will work. We have yet to set up the heating manifolds. But I’m pretty sure they will work just as well as aluminum fins and definitely better than nothing at all. I don’t see any issues coming up either.

So we happily installed the flooring.

This pic shows the layers. First [...]]]>

We found about 500sq.ft. of 5 inch wide maple plank flooring in a dumpster. It had a very slight warp to it due to it not being installed correctly. But with a little sanding we could get rid of that.

So we happily installed the flooring.

This pic shows the layers. First Pex tubes in sand/structolite mix with stringers 16" on center. Then some paper. Then the wood nailed into the stringers.

Despite our good intentions there were complications….
1. Maple is not a good choice for radiant floor heating since maple bows, warps, expands and contracts more than other woods when there are humidity swings.

2. Wide plank flooring is not good when there are humidity swings because it expands and contracts more than narrow planks.

We had wide planks. We had maple. We had radiant floor heating.

Then we had just laid the sand/structolite mix around the tubes. And my ex-carpenter didn’t give the mix enough time to dry before putting the wood down.

And my ex-carpenter nailed the planks in as if they were narrow plank oak over a normal floor, that is to say he nailed the floor down WAY too tightly. Wide plank, maple, radiant, these are all reasons to lay the wood down with some space between them so they can move.

And sure enough the wood warped immediately. I fired my carpenter.

With my new carpenter we have taken the wood up….yes these free planks of wood, valued at around $3500 for that many square feet, are no longer free. But no worries. We are still way ahead of the game.

The new plan is.

1. dry the wood out.

2. Let the floor dry out.

3. Seal the wood on all sides so that it doesn’t absorb water as well.

4. Before laying the wood we will put a real vapor barrier on the floor.

5. Then if all goes well we will just have to sand out the original bow and have a great, salvaged, affordable floor!

I’ve put pex tubes between joists under the subfloor. that is how my radiant guy designed it. The whole theory that as long as you contain the heat it will get to the room eventually etc, etc. I also couldn’t put them above the floor due to a low ceiling.

Since then I [...]]]>

I’ve put pex tubes between joists under the subfloor. that is how my
radiant guy designed it. The whole theory that as long as you contain
the heat it will get to the room eventually etc, etc. I also couldn’t
put them above the floor due to a low ceiling.

Since then I have realized the virtue of using things to pull the heat
out of the tubes. Concrete is good and cheap. We all like heated
concrete slabs, right Then you have aluminum fins. Good, but
costly.

So this week I’m going to experiment I’m going to pile a mixture of
sand and small amounts of cement/water onto a strip of plywood and
then press and screw the plywood up against the pex tubes and
subfloor. The concrete will squeeze around the tubes and create a mini
concrete slab! The floor is strong enough to hold it.

The idea is that the concrete will pull out the heat. It is a dense
mass so it will take longer to heat up (and cool down). I don’t need
the instant heat gratification that aluminum fins would give because
the house is hyper insulated and will change temperature very slowly.
If outside temperature changes it will take at least a day for the
inside temp to adjust and that is plenty of time for the concrete slab
to catch up.

We’ll see if it works!

We have a floor with a high ceiling which means we can lay the pex tubing on top of the subfloor instead of hanging the tubing beneath. The pex tubing takes up valuable space and you can only lay it on top of the subfloor if you have the ceiling height.

Having the [...]]]>

We have a floor with a high ceiling which means we can lay the pex tubing on top of the subfloor instead of hanging the tubing beneath. The pex tubing takes up valuable space and you can only lay it on top of the subfloor if you have the ceiling height.

Having the tubing on top is better because the heat does not have to pass through the sub floor.

We laid stringers of wood 16 inches on center over the sub floor. They were about one inch high.

We put a look of pex tubing between the stringers.

Then we covered the tubing with a mix of sand and structolite. This dense mass was added around the tubes for two reasons.

One it creates a good sound barrier between the two floors. And two it pulls the heat out of the tubes and into the room.

Structolite is a mix of plaster and perlite. Perlite makes it very light which is important since it is a wood joist floor. Perlite is also a good heat insulator, which is bad since we want the mass to pull as much heat out as possible. So we mixed it with sand which is a good conductor but heavier. It was basically a balance we had to find between weight and conductivity.

We dry packed the mixture, meaning we used barely any water at all and packed it in manually instead of pouring it. Wood flooring is going over it so we didn’t want a wet mix that would take a long time to dry.

The end result is a nice warm floor that stops sound between the two apartments. Price was also a consideration. Sand and structolite are very cheap yet very effective in their uses here. The labour was a consideration since it took time to pack the mix in. But it still was much cheaper than any other combination that I can think of.

One important point is that we did not put any tubes or mass near the walls. Instead we put insulation. This is to keep the heat inside the house and create a dense insulation barrier between the heat and the cold. This keeps the house warmer and with a lower heating cost since less heat is lost to the outside.

Here is an example for an order form from one of our vendors:

Convective heat transfer is what most of us are familiar with. This is how our forced [...]]]>

When talking heat there are three ways heat or cold moves through space. Knowing these ways is important because it determines what kind of insulation you use or on the opposite end what kind of heating to use.

Convective heat transfer is what most of us are familiar with. This is how our forced air heating system or our baseboard system transfers energy (heat) to a space. Air moves over a heating element, becomes warmer and expands into the space. In a forced air environment, most of the hot air is at the ceiling, much the same way the hot air balloon rises, so will the warm air in a room heated with forced air. Convective heat transfer is the least efficient means to transfer energy.

In terms of insulation convection happens when thee is a crack in the window or a hole in the insulation. Hot and cold air passed through the space via convection. Stop convection by sealing all holes in the house, aka seal the envelope.

Conductive heat transfer refers to two surfaces touching each other. Imagine a metal pan on the stove. If your hand is positioned an inch above the hot handle, you really won’t feel much from the handle, and you can keep your hand there as long as you wish. But, when the handle is touched, your hand instantly begins to feel hot. This is conductive heat transfer. The pot is giving off the energy (heat) in the handle to your hand in a very fast, efficient manner.

Conduction is one of the more efficient modes of heat transfer. In home insulation you reduce it by putting bad conductors between good ones. Wood conducts heat well so you would put a material like foam that conducts poorly over the wood studs to reduce heat loss.

Radiant heat transfer is the best because it isn’t slowed down by air. Radiant energy is only felt when the energy wave strikes another surface. This means the surrounding surfaces all reach set temperature. By enclosing your body by warm surfaces, we can better control how our bodies lose heat. Radiant floor heat means better comfort with higher efficiency.

To reduce radiant heat loss the best materials are ones that literally reflect the heat. These are foil covered insulation and types of silica that also reflects heat.