Hearth extension?

[hamsey]

Is there anyway to build a R .8 in 3/4" of an inch? I need to keep it flush with the existing hearth. If I go any higher I will not have the lintel clearances I need for a new stove. Not sure if there are any options. Micore 300 is out due to it not having load bearing properties. Saw something called Duraboard LD or HD but not sure if I can buy it. My plan was 1/2" board and 1/4" Tile. Existing Bluestone hearth is about 1/8" higher than the wood floor so I figure that could be the difference for the glue.

Any help would be appreciated. Thanks!

 

[Fsappo]

Micor

https://www.hearth.com/talk/threads/micore-160-or-micore-300-for-hearth.62937/

Use the search feature and look for other Micor threads that may be helpful.

 

[begreen]

One option would be to cut out the sub-flooring in that area to gain the necessary depth (estimate 2"). Then build it up with 3/4" plywood and 2 layers of 1/2" Durock Nex Gen, then the 1/4" tile.

 

[Typ0]

I don't understand from your description why you can't build it exactly like your existing hearth...

 

[hamsey]

Existing hearth has solid concrete blocks supporting the bluestone which rests on a wood beam. Area I want to do the extension has 3/4" plywood subfloor and 3/4" hardwood floor. I want to just remove the the hardwood floor and build up the extension on top of the plywood.

 

[begreen]

This product is pricey but it has a good R value for 1/2" and you can tile on it directly.
https://www.hearth.com/talk/threads/skamotec-225-alternative-to-micore-hearth-pad-material.134910

 

[hamsey]

Begreen,

Thank you!

 

[Skamol - US]

Just an FYI, Skamotec 225 only is available at the following size: 1.5'' Thick x 48'' W x 80.31'' L. The R-value is 3.56 per 1.5''. Thanks to Begreen for the link to the previous thread.

 

[begreen]

Bummer. This is a fairly common request. Does Skamol make a 1/2" thick product suitable for tiling that has a decent strength and insulative value?

 

[Skamol - US]

The short answer, No.

The long answer: Skamol produces various sizes in all of our products ranging from 1'' and thicker: Skamotec 225, Skamolex (vermiculite) and etc. However, all of our products are manufactured in Denmark. Due to freight issue, only certain sizes are available in North America. On Skamotec 225, we only have available 1.5''. On Skamolex, 1''.

 

[begreen]

OK, looks like it's back to plan A hamsey.

 

[Promafour]

Bummer. This is a fairly common request. Does Skamol make a 1/2" thick product suitable for tiling that has a decent strength and insulative value?

begreen,

Promat PROMAFOUR is available in 1/2" thickness with excellent strength and good insulating value (R of 0.4 for 1/2"). If a higher R value is needed we have our Promasil 1000L board available in 1" thickness with an R value of 1.8 per inch.

 

[begreen]

That is about the same as Durock Nex Gen. He needs R=.8 in a 1/2" sheet to work out his original plan. If the Promasil 1000L was available in 12 or 15mm it would work.

Where are Promat materials being marketed? Are they available retail in big box stores or lumber yards?

 

[Fsappo]

Look at these r values guys joining the forums! Great to see!

 

[hamsey]

I can work with 1" if I can tile right over it. Is this doable Promafour? Is so where can it be purchased?

Thanks!

 

[Promafour]

That is about the same as Durock Nex Gen. He needs R=.8 in a 1/2" sheet to work out his original plan. If the Promasil 1000L was available in 12 or 15mm it would work.

Where are Promat materials being marketed? Are they available retail in big box stores or lumber yards?

Currently we are marketing direct and actively working to establish nationwide distribution. I'm happy to provide additional details and information as requested.

 

[Promafour]

I can work with 1" if I can tile right over it. Is this doable Promafour? Is so where can it be purchased?

Thanks!

Yes, you can tile directly over the PROMAFOUR. You can work with it the same as with Hardie backerboard. The primary difference is we can supply in 4' x 8' sheets. Also, one side of our product is pre-sanded meaning painting takes much less time and much less paint. No skim coat or additional processes are required. We also supply a filler material for screw holes or similar that doesn't shrink or crack. The primary feature of the system is no cracking of the surround after heating. Please view the video below for more details.

 

[hamsey]

Attaching some photos to get some ideas/suggestions. How far it needs to be extended depends on which stove I end up with. Would like to end up with WS PH but we shall see.

 

[begreen]

I was wondering if a mason could raise the lintel, but now see that will be a challenge. Does the Clydesdale have a damper-sealing block-off plate installed?

One option would be to put a hearth extension board in front of the PH. It should have a couple screws in it to avoid shifting. This could be removed in summer. The other option would be to remove the flooring and subfloor in the extension area then cut down the top of joists in that area a little bit, insert new 3/4" plywood then 2 layers of Durock and tile.

http://www.woodlanddirect.com/Wood-...ns/HY-C-Black-Type-2-Hearth-Extension-18-x-48

 

[hamsey]

Yes to the block off plate. I found the thread: https://www.hearth.com/talk/threads/advice-on-designing-hearth-flush-to-floor.126713/ Not sure how the OP made out. Now I have access to all the steel, Aluminum and stainless steel I want. I cannot find any r-values for metal. Does anyone know those? Maybe I could go with the blocking/reinforcing/plywood, 1/8" steel plate (or stainless), 1/2" insulating board, 1/2" cement board and poured something for the top. Poured something because it has to match well with the existing bluestone to get approval by the wife. She really does not want me to change anything but if I have to I will overrule that as long as it looks good. Also going by the book I had a discussion with my brother and he said the same thing about the screws possibly being conductive to the joists below. I have screws the will screw the steel to wood so no worries there.

Think that would work?

Anyone know where to get 1/2" Micore 160. Can find 300 but not 160.

 

[begreen]

The heat transfer through a couple of screws at that location will be trivial. Two layers of 1/2" Durock NexGen will get you to your required R value.

 

[hamsey]

Screws might be directly under the stove depending on what we end up with. Think I would need to worry about them? Was going to do I > R 1.0 hearth just in case I needed more. Waiting to hear back from dealer/hearthstone about a trade in.

 

[hamsey]

Ok, Got the deposit on a PH. Only going with R 0.8 hearth. Another question: Does anyone know where I can get 1/2" thick bluestone veneer or something close to match existing hearth?

 

[ssoucy]

I bought all my blue stone at Wethersfield Building supply. Many sizes and much lower than most other places I checked.