Mullins Luxy Build

[DavidApp]

Hello Mullins

Russell's design is a good use of space. Getting into the corners for wood is no fun.
I have a wall across the middle of my stand. and will probable not use the area under my oven for wood storage. My build is under cover so it is not typical. I will use the wood from my wood stove rack.

David

[DavidApp]

I am going to contact the stone supplier to see what I can put on it to enhance the look of the stone.

I left the form on till the end of my build because it gave me something to stand on as I worked on the upper parts of the dome. I think a few days to a week is the usual time to leave the form on the slab. Longer is better.

David

[Mullins]

Hi, I was trying to add picture to my last post as the original pictures did not upload, but it would not let me. Original post below, with the pics that were meant to upload. As I repost, it is possible the original pics were too big...

"Onwards and upwards. The prep for the pours seems to take longer than I think!

Hearth is 10.5cm (4 inch) with 10mm rebar on 27cm (10.5 inch) centres . it took 10.5 bags of 40kgs (88lbs) each and I could have done with and bag or half bag...

Happy enough with the results. How long should I leave forms on for?"

[Mullins]

I am going to contact the stone supplier to see what I can put on it to enhance the look of the stone.

I left the form on till the end of my build because it gave me something to stand on as I worked on the upper parts of the dome. I think a few days to a week is the usual time to leave the form on the slab. Longer is better.

David

Hi David,

I was thinking of the supports underneath the slab, and not the forms around the hearth. It's the usual impatience to see how it turned out (especially after my arch collapsing), tempered by the fact that I think I should leave those supports as long as 2-3 weeks at least, as I don;t want this one collapsing!

Thanks

mullins

[Gulf]

Hi David,

I was thinking of the supports underneath the slab, and not the forms around the hearth. It's the usual impatience to see how it turned out (especially after my arch collapsing), tempered by the fact that I think I should leave those supports as long as 2-3 weeks at least, as I don;t want this one collapsing!

Thanks

mullins

You should be good in 3 weeks, if you placed wedges under the supports to allow for easy removal. In 28 days, that concrete will be everything that it is ever going to be. If you did not put wedges under the supports, I would wait the full 28 days.

[Mullins]

Thanks Gulf

, I will leave them 3-4 weeks then? I did put in wedges on all supports, but I reckon some of them will still be tight to tilt once the wedges are out? I may loosen the posts by removing the wedges, but may need to cut out half the supports...

mullins

[Gulf]

Great! Just, don't get yourself in an awkward position under there with a saw. At 3 to 4 weeks the 2 x 4's should be the only thing receiving any damage by being pried or hammered. Be careful .

[Mullins]

Hello,

As I wait for a couple of weeks to remove my supports I think my build will go into hibernation (from a building point of view). I still have to plan my next steps and phases, and can probably start on my prep...

I haven't investigated too much on the below oven insulation, so would like to investigate and plan this phase now.

As I understand the two options (or two main options) are Vermicrete or Ceramic Fibre Board? Anything else worthwhile worth considering? Is ceramic fibre board calcium silicate?

Anyone have their pros/cons on the two options? Are there other options. As I understand vermicrete is cheaper, but is not very strong and can disentegrate or chip away if not protected? And CF board is expensive. I am somewhat afraid of the CF board leaning/collapsing or being uneven after reading a few threads (long time ago, so I cannot remember)

If anyone can point me to any relevant threads or has any advise, please let me know,

Mullins

[UtahBeehiver]

FB's board is Alumina based vs Calcium based. Perlite is similar to vermiculite (expanded shale) and used the same way by combining with cement. One more option is FoamGlas (tm) which is glass based (like a closed cell foam except glass). Insulated fire brick is also an option. IMHO, here is a little matrix of floor insulation. There may be others and anyone is free to chime in.

Medium...............Cost......... Thermal Properties......... Structural Properties................... Water Resistant
CaSi or AlSi....... High.......... High................................ Medium....................................... Low
V or Pcrete........ Low........... Low/Med......................... Low(Shear) Med(Compress)...... Low
Ins. Brick........... High.......... High................................ High............................................. Med
FoamGlas......... High.......... High................................ Low(Shear) Med(Compress)....... High
Sand/Bottles..... Low........... Low................................. Low/Med.......................................Depends
Hebel/Ytong......?.................?.................... ..................High............................ ...................Depends
Aerated Conc....Low............?.......................... ............High.................................. .............Depends - Refer to David S link http://www.fornobravo.com/community/...-foam-concrete

Sorry, set up a table but it did format correctly. So just follow the order by each medium.

[Mullins]

Thanks Russell,

The table actually reformats if I turn the ipad sideway. See attached pic for anyone interested

I am guessing the insulated firebrick is the Insblock I saw some people talking about?

Cheers

Mullins

[Gulf]

Insblock is "mineral fiber board". And, some of the newer formulas for CalSil board is being marketed as water resistant.

[DavidApp]

Hello Mullins

I replied to this thread several days ago but it turned up in Tips and Tricks?

I made 2 blocks of Perlite/Cement to go under my entry columns. It was a 5:1 ratio and I was surprised how strong it appeared to be. The edges would crumble but it had good compressive strength.
I went with FB because I did not want to gain too much height under the floor. I did consider using both Perlite/Cement and FB in combination.

David

[Mullins]

Hello,

I posted this on Sunday, but it obviously did not post...

I have shut my build down for the winter after having two nights with ice and frost in October (very mild since however!). I went to the builders suppliers on Saturday to investigate my under hearth insulation. They never heard of ceramic fibre board, and could only suggest autoclaved aerated concrete. The blocks would be 10cm tall and are made by a company called H+H. The builders suppliers do not have the technical specs of the product and it comes in at euro 2.50 ($2.75) for measurements of approx 4.5"x20"x10". I understand aerated concrete is similar or the same as Hebel? The guy told me they are insulating blocks used to build an insulated house.

The price alone makes me wonder if this is suitable, as if it was any good, I would assume everyone would be buying this product instead of the other more expensive options as outlined by Russell, Gulf et al.?

Has anybody used this product? Any feedback?

Thanks,

Eoin

[david s]

FB's board is Alumina based vs Calcium based. Perlite is similar to vermiculite (expanded shale) and used the same way by combining with cement. One more option is FoamGlas (tm) which is glass based (like a closed cell foam except glass). Insulated fire brick is also an option. IMHO, here is a little matrix of floor insulation. There may be others and anyone is free to chime in.

Medium...............Cost......... Thermal Properties......... Structural Properties................... Water Resistant
CaSi or AlSi....... High.......... High................................ Medium....................................... Low
V or Pcrete........ Low........... Low/Med......................... Low(Shear) Med(Compress)...... Low
Ins. Brick........... High.......... High................................ High............................................. Med
FoamGlas......... High.......... High................................ Low(Shear) Med(Compress)....... High
Sand/Bottles..... Low........... Low................................. Low/Med.......................................Depends

Sorry, set up a table but it did format correctly. So just follow the order by each medium.

Russell,
An excellent comparison in an easy to read form. There is another alternative that I use a lot which is both cheaper and less water-absorbant than verm or perlcrete and that is what I call foamcrete, I am surprised nobody else has followed my lead. See "foamcrete" under finding building materials.

click here
#1

[UtahBeehiver]

David,

I remember now you experimenting and researching aerated concrete as an insulator. In my old line of work, we used it a lot as lightweight structural fill over our high pressure natural gas pipelines where wheel loading was a factor. Never did any work on the thermal end of the foamcrete though. So I am interested foamcrete projects have fared since 2012. You do stretch the boundaries of concrete with your work area over the kiln and foamcrete, etc. Nice to see some outside the box innovations. I will add foamcrete to the matrix but defer to you and the thread link a a resource.