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Reply With QuoteAnd you call yourself a "Super Genius"Originally Posted by Headpin
I'd love to vote, but I don't see the "No Idea" option...........
Good Luck
Tell us all why you have no idea, that is why I asked.
Your Home Technical Manual - 4.9 Thermal Mass
Adding thermal mass in the floor of timber framed house G'day all and another question about our renovation plans and ideas.
I have been reading though the "Technical manual" and would like to have the benefits of some thermal mass in the floor in the lounge room that is exposed to the winter sun.
20 -20 hind-sight says we should have had some extra stumps put in but no big deal.
The technical site says we can add extra mass easily using poured concrete in a suspended slab supported on the bearers.
The room is only 3600 wide and the winter sun only shines on the first 500mm of the floor.
I know that the thermal mass will be smallish but any improvement will be of benefit, before we pay an engineer I want to get some idea of how this could be done so we can think about the cost/benefit ratios and whether or not we can do it ourselves; I am confident with concrete and have a decent mixer for the small quantity required ( or a mini mix batch from the mob at the end of the street )
We would of course insulate the bottom of the slab afterwards.
What is the possibility of putting in a bearer at 500mm sealing the bottom of the joists with form-ply and just filling in the holes between the floor joists??
It isn't a lot of concrete, about 200 liters, or 350/450Kg but we would tile over the top with matt black tiles
I have an idea in my head about adding an internal brick wall beside the chimney and, breaking open the plaster wall and putting in a beam at the top with jack studs and thermal mass inside adding extra bricks above the mantle, from the edge of the fireplace to the ceiling. The chimney base is really solid so should take the added mass.
We would then add an batten out the chimney ( we have some 40mm Tophat section ) and beyond the 40mm air gap we would insulate with a pack of rockwool.
Last inter I could feel the heat radiating from the external wall of the chimney; I hate to waste all of that thermal energy to the sky when firewood is so expensive.
Any and all opinions are appreciated, they will help us in the decision making process
And you call yourself a "Super Genius"I'd love to vote, but I don't see the "No Idea" option...........
Good Luck
Tell us all why you have no idea, that is why I asked.
Your Home Technical Manual - 4.9 Thermal Mass
Gotta love ya mum, after all mothers are always right.
The better way is to construct a trombe wall - do search on this site and the web and you'll get some info on it. I've used them plenty and they work well. Need thought about placement and design and they are heavy so supporting on timber sub-floors needs care too.
Another alternative is a water body - so a tank inside or a pool - but again this needs much thought and knowledge of the specific house.
Advice from me on this forum is general and for guidance based on information given by the member posing the question. Not to be used in place of professional advice from people appropriately qualified in the relevant field. All structural work must be approved and constructed to the BCA or other relevant standards by suitably licensed persons. The person doing the work and reading my advice accepts responsibility for ensuring the work done accords with the applicable law.
Trombe walls work well but in this room not possible as we need the view to resell or rent the house in the future, we are just researching cost effective ways of being as green and efficient as possible within our budget.
Adding thermal mass inside the house after retrofitting insulation to the walls was; we thought; one of the best solutions; in this house; in this area.
I like the idea but as you seem to be well aware, your implementation of the idea is what will make or break it.
My brother has recently built a half concrete, half stilt house (rather than the normal cut and fill method used over here) - while it looks great, the stilt (wooden framed flooring) area is uncomfortable due to temperature swings throughout the day - he's now just killing it with an oversized aircon.
Personally I'll be watching how you go with this idea - as I can see the potentially significant efficiency benefits. Good luck.
If the following have not been done;
1. Double glazed windows
2. Ceiling and wall insulation
3. Under floor insulation
then I would do them first.
If the fireplace is for an open fire then I would replace that with a combustion heater which will probably triple your efficiency.
Good luck.
I just love sheepies!
Roof now has R2.1 Anti-con, ceiling we will clean and use R3.5 Fiberglass between the joists, roof is vented using one of the old style "Thinking Cap" roof vents and very soon we are pulling off all the weatherboards on the Western exposure, fitting "Foilboard 15mm " , battening out and sheeting with Hardie flex or similar.
The fireplace has a "Coonara" with about 10 or 12 years of life left in it, I'd like to double the efficiency of the inbuilt unit with the secondary heat exchange in the chimney
I forgot about the double glazing and under floor insulation.
Under floor is easy, plenty of access now, we raised the house 55mm and all the dirty batts from the ceiling can be used as the dirt will fall off eventually I suppose.
The windows are huge; 2700 * 2100mm and Aluminium framed, we cannot afford to replace with double glazing ( we were quoted almost $3500- to replace this with a double glazed unit ) so we were thinking of using a double layer plastic film on a timber frame there.
If you have a look at some of the Grand Design programs (the cruciform house springs to mind) they used beam and block floors. Basically structual concrete beams with concrete block infill. That might be an option as a retrofit. One hell of a retrofit though....
Well it seems like I misread the sun angles too.
In summer we get 500mm of sun on the floor, in winter we get over 1600mm of sun shining on the floor so that means more extensive mass but more worth while, and I know what that means.
Structural engineer and a proper engineered slab because what we have as sub-floor won't take 2 tonne plus live load I am sure
Still investigating this idea.
We will be going ahead with some extra mass next to the fireplace tho, just a few courses of bricks on either side, I don't want to add any more mass on thew house structure without making the subfloor stronger but I cannot read the span tables with my system.
I have a few 90 * 77 plywood bearers left over from the stumping job as well as 4 off 100 * 100 concrete stumps 900 tall, I was thinking that I could add an extra bearer on each side of the fireplace BETWEEN the existing bearers, easy job, but I am getting old and stiff and want to work as close to the edge as possible.
I have 2 * 1300mm offcuts and the existing stump spacing at the chimney point is 1850mm, I am assuming it is OK to place one stump under the bottom plate and the other where the bricks will finish at 600mm in from the bottom plate with an overhang of 700mm but want to check, can some-one who can read the span tables please let me know?? Otherwise I will just cut the bearers at 700mm
We will be using 15mm compressed concrete sheet as a base to mud the bricks in and perhaps tiling over those although I want to expoxy varnish the bricks Cecile wants tiles around the perimeter of the walls
I hate to sound like a knocker but I think you will get limited benefit from all your hard work.
Thermal mass works best where you have warm/hot days and cold nights so the heat radiates back out of the mass during the night warming the space. You tend to need a fairly large glazed area (depending on the size of the thermal mass) and good solar orientation to make the most of it. The mass also needs to be insulated from the ground to stop the heat drawing away into the ground. Happy to stand corrected...
As others have said I would be looking at other areas such as making the place as airtight as possible, insulation, secondary glazing, installing a wetback on the wood burner and fitting radiators etc...
Andy
Ah if only I had a decent wood oven instead of the Coonara, we are doing all or most of the above suggestions and we are trying to get the absolute most we can out of the materials we have.
Window in question is North facing, 3600 wide; I said the room was 3600; my mistake and is 2500 high.
We have the bricks cheap ( 30 cents each )( plus 275 firebricks if we want real mass ) and I know that using the chimney as a heat exchange thermal mass works because I have done it once before, besides I like the rustic look of exposed rough laid bricks also we have to bring the fire surround out to comply with new regulations.
Geelong has temperature swings of 12 - 15 degrees nite/day during summer. Reading the technical manual I was under the impression that 6-8 degrees made utilising thermal mass a realistic proposition
This is a good read if you haven't already come across it...
Thermal Mass, Building Comfort & Energy Efficiency | ecospecifier - products/knowledge/solutions
Especially the bit about north facing window area, 13.5% of floor area for Melbourne. Seems I was wrong about insulating under the slab but my gut feeling is the floor would cold under foot during winter. I guess rugs in winter time would help allieviate that. Still need to insulate under the thermal mass if it is suspended and the underside is exposed.
Moondog, it'll never work you know why, too!
it's cheaper and easier to do this stuff at construction stage. this house will suck up more money than it's worth, and in the end won't give as much cost benefit as if we were going to retire here...which we aren't
sorry to burst your bubble
Bubble bursting hurts, also my ego is dented.
Hi Andy, most of that material I have seen elsewhere, interesting synthesis tho, Does any-one here remember the "Whole Earth" magazine??
This is all old hat to an aging hippie, heck I still like bottle walls and 44's filled with water, they just do not look pretty and take up valuable stereo room.
Wrong forum, Ted!
I'm afraid I am with Andy on this one. If you had a slab poured while you were building - fine. But installing a floating slab inside an existing timber house is opening up a bit of an ants nest of potential problems, the engineering for supporting the slab being only one of them. While i applaud your enthusiasm for increasing the house's efficiencey, I am also a little perturbed by your comment about future selling. One factor to consider before investing all this time and money is - will the alteration make your property so much more desirable that people will pay the difference between the value it had before you started and the cost you have incurred in carrying out the work?
I would hate to buy a timberframed house and discover that part of the floor of one room was one material and the other part, another material.
Work on the small jobs and get them sorted - I suspect you will be amazed at the difference it makes in cold (and hot) weather.
Just had a thought!!! while it will not achieve quite what a slab would achieve ... why not tile the floor of the relevant room with thick terracotta tiles? The colour would draw the heat, the material retain it, and you would have an attractive floor covering that you can place the odd rug on for comfort ....
Thanx Black Cat
That may be a reasonable compromise; Cecile does want to tile around the edges and I think that we could find even a little mass ( yes I am in the process of fixing the underfloor insulation ) makes a difference, I could happily live with rugs on a tile floor, what exactly is the difference between terracotta and quarry tiles?? they look the same in pictures but I have never done a side by side comparison.
Moondog
As more recently pointed out, I'd be definitely going for a floor construction based on either compressed cement or Scyon (James Hardie) with tiles over the top and Rockwool insulation underneath. This shouldn't require additional framing and will provide 'some' thermal mass to help even out room temps.
Beware of the rug though....in the winter it will insulate the floor from the incoming warmth of the sun. Yes it might stop room reflections from your hifi but it will compromise room comfort....so be prepared to move it around.
Terracotta tiles are just that - terracotta or clay. Quarry tiles tend to be made of a hybrid of ceramic materials. The thing to watch for is whether the top colour is the same right through the tile or not. If the latter then they will discolour with wear over time.
Now go back to the stereo net.
Joined RF in 2006...Resigned in 2020.
PaPaPLeeese!!!!!!!!!!!!!!!!
DIY Audio.com
Actually we have a lot going on in this house so thie thread is one of many
Thanx for all you help and serious comments; we have a lot to learn and not much time to do it in
Regards
Ted
What SBD and Blackcat said (but stereo optional)!A compressed sheet base and good tiles with underfloor insulation will give a good result. I have some 'in-laws for whom we who used 25mm terracotta on top of 20mm sheet with good underfloor insulation (in Canberra so cold) and good solar aspect in winter and it captures an retains heat very well.
Advice from me on this forum is general and for guidance based on information given by the member posing the question. Not to be used in place of professional advice from people appropriately qualified in the relevant field. All structural work must be approved and constructed to the BCA or other relevant standards by suitably licensed persons. The person doing the work and reading my advice accepts responsibility for ensuring the work done accords with the applicable law.
Then compressed sheet and tiles is what I will aim for.
This is of course at the end of the list of improvements but moderating temperature swings inside the house will make it much more comfortable and with good use of materials we should see a reduction in our energy consumption as well.
I assume we can lay the compressed cement sheet over the existing pine floorboards?? If we lay a 900mm sheet will the dead-load be too much for our current stumps and bearers??
Over floorboards - highly unlikely to be any risk to the load bearing capacity, but like everything depends on the specific dwelling and conditions.
Advice from me on this forum is general and for guidance based on information given by the member posing the question. Not to be used in place of professional advice from people appropriately qualified in the relevant field. All structural work must be approved and constructed to the BCA or other relevant standards by suitably licensed persons. The person doing the work and reading my advice accepts responsibility for ensuring the work done accords with the applicable law.
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