Speculative–retro fit of heating system
Hi, all, please remember I’m only an amateur here and be helpful, don’t make fun of me.
So say I had a situation like this to deal with.
A slab on grade house to renovate. The house built in the fifties. The heating plant is/was an oil burning furnace and boiler. Copper piping ran through the slab with hot water for heat. The slab was covered with asbetos tiling. Currently covered with wall to wall which will be removed.
The interior and exterior walls in this house were originally some kind of cinder block. In 1970 when an addition was added the block was furred and covered with wallboard. You can still see the block in the closets.
A long time ago, the house was unheated over the winter, and there was damage to the piping in the slab. So the house has been unheated for a LONG time. The addition is frame above crawl, I think, and has electric baseboard heat.
So if one were to renovate this house, given the constraint of the original block walls, through which I assume you can’t run duct work, what kind of heating system could you put in? Are there any contemporary in floor radiant systems that could be used without tearing up the current slab and disturbing the old tiles and messing at all with the old heating piping?
Thanks for any ideas.
Replies
There are radiant systems that use aluminum channels as a heat sink and a place to put the tubing.
You can also anchor the tubing to the floor and put a layer of Gypcrete on top. Wood furring strips are placed for a subfloor or hardwood floor.
Both methods above will take about 3" away from your current ceiling to floor distance. Neither falls into the "cheap" catergory. New heating loops would be run within the constarints of existing walls. You could zone different rooms/areas.
Odds are that the existing copper is in contact with concrete and it will fail in other places eventually.
Or, if you have attic access, you could install a Unico high velocity system with a water heating coil and get AC too...
Or you could do the electric baseboard thing elsewhere...
From the sound of it I am guessing that this is a complete gut job. In that case the floor overlay with radiant should work unless it already has low ceilings. That does not work in finished houses because of problems with things like cabinets and stairs and exterior doors.
But ducts are not normally run in outside ways (in most cases). A new one story house on slab usually has a furnace either mounted in the attic or in a central location and then feeds duct work in the attic.
Again in a complete gut job that can usually be done also.
There should be at least 2 places to run ducts thru the block wall without structural impact.
That and the crawl space in the addition would lead me to pick a Package heat pump bought off the internet (no EPA freon license needed, DO NOT buy any reesistance heat backup*) and locate the package HP at the addition/old part interface on the outside of the house. I'd abandon the pipe in the floor, but maybe leave some of the elec BB heaters in place just for those once in 25 year cold snaps in PNW.
Many consider insulated flex duct a poor choice, but in the Portland climate it will be OK especially if you throw some more insulation over it and install it in the 'attic' or crawl space. The flex insulated duct is relatively inexpensive at the big boxes and easy to install. You could probably get by with one 18" hole and one 10" hole in the block wall, or even just leave a door open between the new addition and old part insead of the 18" hole for the return for the return.
*have never needed it in Seattle.
Folks, this is exactly the sort of input I needed.Junkhound, the house is not here in Portland, it's back east. (This is the house I grew up in. My Dad's not done any maintenance; the house has been empty almost 25 years. We have to figure out how to deal with it, and I'm at the beginning of the process.) The climate is colder by a good bit, IIRC.I hadn't even thought of the possibility of using the attic for ductwork. That's exactly why I asked the question here.The addition and the main house communicate via one door that is closeable, and one opening about 8 feet wide between two living areas. Two separate attics, I believe, but aligned in such a way that there's no reason they can't communicate.Danski, thanks for the info about the radiant system and how it impacts ceiling height distance. I knew it would in some way, just didn't know by how much.Bill, yes, it's very likely it's a complete gut job. We haven't gotten to the decision point yet on doing it or not, but I was thinking ahead.Thanks all, this is what I needed, possibilities. I'll have more questions I'm sure when I'm on a laptop and standing in the actual house. And they'll be a ton of questions if we decide to rehab this place.
Attachment is trade study done for GGrandmas house in IL. It had hot been heated since 1975, next door to my parents, Pop used it for storage after GMa's death.
1300 sq feet, 2 story typical 1900 midwest home, Grandpa built it, looks like nephew may live in it for awhile even in a few years as a starter, now used by brother as photo studio.
Brother has gutted it in the last 2 years and insulated the walls/ceiling. I installed a HP/AC 2 years ago as described in first post. Did install the backup resistance heat for that location (can get to 40 below on rare occasions).
If interested, e-mail me and can send some pix and the excell spreadsheets for the insulation/heating, etc. trade and cost studies we did.
Check the power company offers where your house is for rebates. The HP rebate in Spfld was $400; so, the entire HVAC installaion (total DIY of course) including a new 200 A service, 4T HP, and ducting was under $1500 out of pocket and about 3 days work.
PS: the quilt stand is still being used next door, Mom elected to stay in the house after Pop died, they lived there since 1945. The 1300 sq ft house is next door, it will be 100 YO next year.
Art B.
Edited 5/27/2006 7:26 pm ET by junkhound
Dear All,
There are various radiant floor heating options that won't have to take 3" of floor height. First is a 1/2" plywood system, either Quik Trak or Climate Panel, depending on brand. These can be shot down directly with "Hilti" fasteners or attached to a plywood subfloor also shot down. Another option is an aluminum plank system from Rehau which is 5/8" high, this system can simply lay on the existing, assuming it is FLAT, like a floating floor. There are plywood turn panels and spacers available. Also, there is the gypsum solution. This only needs to be 1 1/2" thick with 1/2" tube. A thinner diameter tube can reduce the gypsum height, as long as you don't have less than 3/4" of material over the tube for a thermal mass. There are also gypsum thickness minimums, depending on manufacturer.
Of course, all these dimensions don't include finish materials, but I'm sure they will all be under 3".
Yes, you can do forced air either as a stand alone unit in the attic or fed with hot water. This system will also give the A/C option.
Of course you could also simply install hot water baseboard. I assume the boiler is in decent shape so you won't have to buy one, zoning is your option. Individual pieces of BB can be fed with 1/2" PEX, don't exceed ~20'. This can be an economical option I have had to do for slab houses. Yes, you have to deal with covering the pipework coming down the wall in the corner, but the heat is on. And that's the important thing in the North East.