I am afraid you will have to clarify what you mean by "slide-in cooktop." What exact nomenclature does BS use to describe it? (I.e., is it a range-top or a cooktop?)

The 6" figure with which I am familiar is a requirement that you must use nonflammable materials for behind an installation that uses island trim. I used a piece of cement board in place of the drywall behind the range.

Edited to remove sleep-induced typos

This post was edited by Angie_DIY on Thu, Apr 4, 13 at 13:56

I believe that Bluestar calls is a rangetop ( there is no oven). The existing cabinet that this is getting installed over has a wood cabinet back wall. I understand that the upper six inches of this space now needs to be non-combustable. What have others done as a solution? Can I install a piece of sheet metal cut to the appropriate dimensions?

The image is of a larger range top...mine is the 24 inch version with 4 burners.

This post was edited by maym on Thu, Apr 4, 13 at 11:38

I'm pretty sure the 6" of non combustable is to adjacent cabinetry (uppers) on the sides, and above the rear vent, not below the range top. I would check with Bluestar for clarification.

I think that you are correct...this is what I believed when I called Bluestar last week..however, the individual I spoke with stated it differently and this led to my confusion. I will call them again.

No, ctycdm. There is a requirement for 6" is below the top of the rangetop if the island trim is used. (There is also a 6" side clearance requirement you mention for combustible surfaces to the side of and less than 18" above the rangetop):
From the installation manual for our Bluestar rangetop:
Note: If the island trim option is used without the 6” clearance recommended, a non-combustible rear wall extending a minimum of 6” below the countertop must be used. In no cases will we accept responsibility for claims which may result from heat damage to a rear wall or counter, including cosmetic damage. It is the responsibility of the owner/end user to ensure that the material used in such applications is not only non-combustible, but is also truly heat resistant.

Mayam, the requirement is 6" below the counter top.

The rangetop itself is 7 7/8" high from the top of the side pieces to the base of the rangetop. It is suppose to be mounted so the top of its side pieces are 11/16" above the adjacent counter top. The bottom of the rangetop will be about 7 3/16" below the counter top.

Therefore 6" requirement is satisfied by the surface behind the back of the rangetop being non-combustible and heat proof. The cabinet below the range top doesn't need to be non-combustable. Does your cabinet have a back that wiil be behind the rangetop? You probably don't want it to have a back unless your cabinets are deeper than 24" because the body of the rangetop is 24" deep and the control panel sticks out 3" beyond that so you want the rangetop completely over the cabinet below it rather than sitting in front of a 3/4" cabinet back.

Assuming the cabinet is below the rangetop, you would just need to tile down the wall behind the rangetop to the cabinet top (or at least to 1" above the cabinet top.

Ours is installed in an island and the cabinet it sits on is below it (i.e that cabinet was built about 7" shorter than the other cabinets. There is a cabinet behind the rangetop facing the other side of the island and our GC put a metal flashing between it and the rangetop because of the non-combustible requirement.

I don't have a picture of the cabinets with the metal flashing installed because it was done shortly before putting in the range top, but you can see in this picture the area behind the rangetop where we needed it.

This post was edited by cloud_swift on Thu, Apr 4, 13 at 14:07

From the installation manual:
This appliance has been designed to be in- stalled directly against rear walls and side base cabinets. It cannot be installed di- rectly against tall side cabinets, side walls, tall appliances or base cabinets extending beyond 24 inches [610 mm].

and in another place:

If you are using an island trim a six inch clearance between the back of the range and a combustible surface is required. If an island trim is to be used without this six inch clear- ance the back wall must be non-combustible and heat resistant material that extends below the top surface of the range a minimum of six inches.

That last quote is from a section that is shared with full ranges. My reading of all of this is that you needn't worry about the cabinet upon which the rangetop sits. However, you are supposed to make the back wall non-flammable and heat resistant, extending 6" below the top of the rangetop. As I said earlier, I did this by using cement board instead of drywall.

Here is a link that might be useful: BS Rangetop Installation Manual

OK, I stand corrected, but I did say to check with Bluestar to be sure. Although if this isn't confusing, I don't know what is... "This appliance has been designed to be in- stalled directly against rear walls and side base cabinets." and then - "If you are using an island trim a six inch clearance between the back of the range and a combustible surface is required. If an island trim is to be used without this six inch clear- ance the back wall must be non-combustible and heat resistant material that extends below the top surface of the range a minimum of six inches." Then how far above the range top does that non combustable on the back wall need to go?? Maybe Bluestar should show a diagram, or section to help clarify all this conflicting info.

Hey Cloud_swift,

I'm thinking about having a BS in an island as well, which I understand is not the GW ideal. What was your motivating factor(s)? Also, what type of hood are you using? I'm still in the draft design stage and have yet to post a layout here I will do soon, but I am curious. Many thanks!

Sorry to hijack Maym.

It was designed to stand against rear walls with the taller backs. There's a backguard that's about 7" high above the rangetop and another that's about 19".

The note about needing a non-combustible surface only applies to the island trim which only extends an inch above the range, it can go directly against a rear wall but the rear wall needs a fire proof surface.

Yes, it would be best if they specified how high above the rangetop the non-combustible surface should extend. Probably at least as high as the standard backguard but I think most would take it all the way to the hood. Perhaps that doesn't need to be stated because code will cover it while the requirement for the surface to go below the top of the range isn't standard.

Mgoblue, I've discussed motivating factors on some other threads. I've lined to one relatively recent one below including a bit of an "island tour" of my island. You could post further questions there and it would be on topic without me having to repost everything.

Briefly,
o We've had that layout before and it worked well for us
o I like prepping facing the room and having the burners right next to my prep area
o It left the perimeter available for other things that we didn't want on the island including
-- refrigerator
-- wall ovens
-- pass-through window and sink
-- small appliances and overhead cabinets

We didn't want the clean-up sink on the island and none of the other stuff can go on an island. A gas cooktop isn't suppose to go below an operable window. We keep kosher so we have extra dishware, flat ware and pots and pans so we needed the maximum wall cabinet space on the perimeter.

We have an Independent Hood, the model is Sante Fe Island. I think what was Independent Hood is now Prizer. It is fine, but the front 5 inches on the underside of the hood is a panel for the lights and controls and the hood air gathering space begins after that. If I was doing it again, I'd look for one where that front edge was narrower or that stuff was on the sides or back so it would be a bit more efficient.

Here is a link that might be useful: Thread on island rangetops.

FWIW, I believe the stipulation for 6" non-flammable below the counter is a documentation error by BS (the tech. writer cut and pasted too much of the range manual when creating the rangetop manual).

The requirement makes perfect sense for a range and zero sense for a rangetop. A range will be belching out searing hot gases from the vent; some of those gases may be drawn back down behind the range because the oven burner is drawing air in. So those hot gases might scorch the area just behind and below the vent. Obviously none of that applies to the rangetop.

Before anyone pipes up with fanciful theories about the back of the rangetop becoming hot enough to scorch anything: if that were the case the stipulation would apply regardless of which style of trim you are using, and would also apply to the sides.

Of course, the building inspector will likely be immune to logic on this point, so it's effectively moot.

Thanks Cloud_swift. I found that thread just after I posted (figures!), but appreciate the response here. It was very helpful. Appreciate it.

I have to say I agree with Caliente63. In fact, the page where that text resides on the installation manual I linked shows a drawing of a range, not a rangetop.

The requirement makes perfect sense for a range and zero sense for a rangetop. A range will be belching out searing hot gases from the vent; some of those gases may be drawn back down behind the range because the oven burner is drawing air in. So those hot gases might scorch the area just behind and below the vent. Obviously none of that applies to the rangetop.

Before anyone pipes up with fanciful theories about the back of the rangetop becoming hot enough to scorch anything: if that were the case the stipulation would apply regardless of which style of trim you are using, and would also apply to the sides.

You are right Bluestar seems very focused on the range and the rangetop is just an afterthought - a range sold without the oven below it. They don't seem to do anything special to support the rangetop in their documentation. For example, when we opened the box our rangetop came in, the first thing on top was a single sheet with some caution about unpacking regarding the range door. That made no sense to put in a box with just a range top - there was no door, but it was there. I guess they just did their normal packing the same regardless of whether it was a big box for a range or a flatter box for a rangetop.

However, I don't entirely understand your reasoning above. I can see that hot air from the oven may vent out the vent. But why would the oven burner the exhaust down the back of the range? I doubt that the air intake is on the back of the range which would be against a wall. If it was, a grease fire in the oven might send heat directly out that way and be a fire hazard.

Also, if your explanation is correct, why wouldn't that also be a potential problem with the taller vents? The regular back is about 6" higher so any gases in the vent won't have cooled very much by the time they get to the top of it and if there is something that can suck the vented air behind the island vent, why wouldn't that same suction suck air behind the regular back vent?

But I agree that it is difficult to see a scenario where the rangetop without the oven below needs a non-combustible surface behind it below the height of the rangetop. The island vent (and probably the same is true for the other two backs) has an internal divider in it. The front of the vent connects to the area under the rangetop burners and the back would connect to the oven if it was a full range and is just open to the cabinet below when there is no range.

In normal operation, convection will pull air from that space below the burner past the burner and the oxygen in that air will feed the combustion with the hot air flowing under the pot and up. Replacement air will be pulled in the through the island vent (or the other backs) and through any burners not currently running. So the air going through the island vent for the burners would be cool intake air, not hot exhaust gases.

Perhaps if there was an accident such as grease spilling into the area below the burners and igniting there could be hot exhaust air coming up part of the vent and the back could get hot - but why would the island back get hotter than the regular back in that case?

Anyway, that's why I was okay with our contractor's recommendation of putting a metal flashing on the cabinets behind the rangetop. That's a fairly minimal non-combustible barrier, but there is also the back of the vent, the air gap for the unused oven vent and a metal separator isolating the cabinet back from the rangetop burner vent area.

"I don't entirely understand your reasoning above"

I think with an island trim you can stand the range a little clear of the back wall, leaving a gap. With the taller trims, I think the backsplash has to be attached to the wall, so no gap for hot gases to recirculate.

SFAIK, the air intake is on the bottom of the range.

I doubt this makes any sense in the real world - it looks like lawyer CYA. It bugs me the way manufacturers take the lazy/super-conservative option on a these kinds of things, because it makes our lives more difficult trying to pull our kitchen designs together. Don't get me wrong - I am all for safety, but I have seen too many instructions and warnings that are just way over the top. I guess it's the price we pay for creating an excessively litigious society (we can't simply blame the lawyers - they only act that way because too many of us go along with it and too few of us vote against it).

I am happy that you were able to pay lip-service to the requirement without compromising your installation.

This post was edited by Caliente63 on Sat, Apr 6, 13 at 19:11

Caliente, the two taller back guards are attached to the back of the range/rangetop with the same 6 screws as the island trim. The instructions say nothing about attaching the taller ones to the wall and I don't think they are anchored to the wall in any way. Screws that did that would have to go through the vent and be visible on the front of the backguard and I didn't see any screws or screwholes on the floor model range that I tested before buying our rangetop.

This post was edited by cloud_swift on Mon, Apr 8, 13 at 17:10