Gas hob recess too small for new hobs, what to do in limited space.

[Andy's Shed]

Our 15 year old gas hob has seen better days and it really needs replacing, the problem that I have is the existing recess is too small for all of the new gas hobs.

There's a standard cupboard under the hob, but I'm not sure if anymore of the front of the cupboard frame should be removed to make space for a new hob. I didn't fit the hob and I won't be touching the gas myself, I just need to figure out if a new hob can be fitted in our counter top before buying a new hob.

The existing hob on top of the counter is 580mm wide & 510mm deep and that seems to be fairly common, the existing recess is 540mm wide (poss 545mm at a squeeze) & 460mm deep. There's currently a 50mm space between the wall and the back of the hob on top of the counter top, there's a 45mm space between the very front of the hob top and the front edge of the counter. Most new hobs seem to need a recess of 560mm wide & 480mm or 490mm depth.

There's no room to cut away anything at the rear of the existing recess as it's right up against the back of the cupboard, that only leaves the option of cutting away from the front, which will mean removing most of what's left of the cupboard frame (possibly all of it) and doing that would also bring the new gas hob front even closer to the front edge of the counter top.

What would you do in my situation? Would it be wise to remove the remainder of the cupboard frame at the front? I don't want to buy new kitchen units and I can't find a gas hob that'll fit our current recess.

Some pics, which may or nay not help.




Cupboard front edge



Left side of cupboard



Right side of cupboard

 

[Mickjay]

You say the back of the existing recess is at the back of the cupboard as I understand it, so can't you just notch the back of the cupboard to extend the cut out to the rear? It's what I have done with basic b&q kitchen units.

 

[Terry - Somerset]

There seems little choice but to remove material from the existing top.

Removing material from the front will reduce strength where there is probably maximum stress and least space for reinforcing what is left.

Therefore the back and sides need a trim. If it leaves the top unsupported, some additional changes will need to be made - eg fix batten 10-20mm deep to wall to support rear.

 

[Spectric]

These hobs are often held down with a clamp arrangement from underneath, make sure that when you modify the recess that you can still fit them and the side or rear panel is not in the way.

 

[Bingy man]

I’ve fitted several hobs to existing worktops and as long as there are no critical components or fixtures then you have no choice but to enlarge the opening in situ , obviously kitchen cabinet manufacturers and hob manufacturers don’t talk to each other as you often have to remove part of the cabinet to install the hob . It’s not always possible to fit all 4 of The hold down brackets but a thin bead of clear silicon goes a long way . Good luck

 

[MikeJhn]

Just fitted a new induction hob and it has no provision for clamps, just a silicone mastic seal between the hob and worktop, difficult to believe, but induction hobs have better control than gas.

 

[Morag Jones]

Just fitted a new induction hob and it has no provision for clamps, just a silicone mastic seal between the hob and worktop, difficult to believe, but induction hobs have better control than gas.

And sooooo much easier to clean!

 

[flying haggis]

One saving grace appears to be that the top spar in the unit front looks to be decent ply so a lot stronger than just chipboard like most units. As others have said notch the back out and if you take any out the front I would add a few more screws to hold the unit frame to the worktop so strengthening it. Hob cut out "engineering" never looks pretty!

 

[John Brown]

Just fitted a new induction hob and it has no provision for clamps, just a silicone mastic seal between the hob and worktop, difficult to believe, but induction hobs have better control than gas.

They're a lot more expensive to run, as well! We got ours for the grandchildren safety aspect, but probably would have thought twice if we'd known electricity prices were going up so much.

 

[Phil Pascoe]

We got ours because of having no gas. I wouldn't go back to gas now.

 

[John Brown]

We got ours because of having no gas. I wouldn't go back to gas now.

An easy decision if you have no gas!

 

[Richard_C]

Just fitted a new induction hob and it has no provision for clamps, just a silicone mastic seal between the hob and worktop,

Same here. The mastic seal stops spillages and gloop getting under the rim and stops it slipping laterally, and in any case the recess is snug. Gravity does the rest, unless the Earth passes close to a black hole there are no upwards forces acting on it so clamps seem unnecessary. I replaced a Bosch ceramic with a Bosch induction, frustratingly about 3mm more front to back. Eased the recess with a block plane, but it makes you wonder why there isn't a standard size. When looking for one I noticed that different manufacturers vary by enough to be a nuisance but not enough to be meaningful in terms of functionality.

Having done a few over the years I've concluded that they are all mad and that most installations are a bodge. I've also concluded that you need to unpack and measure/offer up the hob before you start cutting, they are not always as drawn and often have little surprises like awkward cable entries or clamp positions

 

[toolsntat]

One saving grace appears to be that the top spar in the unit front looks to be decent ply so a lot stronger than just chipboard like most units. As others have said notch the back out and if you take any out the front I would add a few more screws to hold the unit frame to the worktop so strengthening it. Hob cut out "engineering" never looks pretty!

Just a note here to say I believe, from the picture, that it is a plywood effect edgebanding on chipboard carcase.

Andy, check carefully the thickness of your worktop and how much space below the surface is required to fit the hob.
I sometimes find that more of the rail can be left intact than the worksurface itself, admittedly its bordering on getting too weak on the front but doable.

As you can see possibly the gas man has munched out the back to facilitate gas connection and I expect it may be the case of needing more access when it comes around to the new installation.
If this is the case then I would remove the back using multi tool to cut down one edge only and replace after the installation. EDIT... back up the bus Stan....just realised the existing gas pipe may prevent this so I'd likely opt to remove in two halves.
And be hoping it's not glued or stapled in.
Not the end of the world but cutting around it all would be required.

Cheers, Andy

 

[Andy's Shed]

Thanks very much everyone, your help is appreciated.

I've had a closer look at the frames and they are just chipboard with a plywood effect laminate, just as Andy suspected.

There's a gap at the back of the cupboard, about 80mm deep to the plasterboard on the wall. The corresponding gap above the worktop is obviously less due to the thickness of the plaster and tiles, that measures 50mm which is the minimum required with the hob that I'm looking at.

I've been looking at the fitting instructions for the possible new hob and they state that there needs to be a minimum of 50mm thickness between the recess and the counter top front edge, not 50mm between the visible hob top and counter top front edge as I'd thought. That allows more wiggle room.

I think the trickiest parts of the recess to enlarge will be the left and right sides, the left side or the current recess is just a few mm from the cupboard frame, so not much room there.

At this stage I'm inclined to ask if my plumber will do the cutting out and fit the hob all in one go, I'm not feeling overly confident in my abilities not to make a mess of it somehow. Also, if he can do it, he's likely to have the right tools for the job, whereas I have a go myself we might possibly be in a situation where we don't have a working hob until he can come over and connect it up.

New hob info.



Back of the cupboard.

 

[flying haggis]

I am sure manufactures could make these hobs such that a smaller cutout is required especiall front and back and could standardise on it but then again why should they make it easier for a competiors hob to fit rather than one of there own. The last two hobs it fitted, ones was a damaged electric one in a rental property and I managed to find the exact same one still on sale so easy peasy (other than trying to cut through the silicon I had been over generous with the first time..... and the second was a 6 burner gas hob in my new kitchen that seemed to need half the worktop in a long run removed! luckily I hadnt fixed the units in place and was able to fix it down and get the gas connected(not by me) and then slide the units in and fix them in place

 

[MikeJhn]

They're a lot more expensive to run, as well! We got ours for the grandchildren safety aspect, but probably would have thought twice if we'd known electricity prices were going up so much.

I can only assume you have a halogen hob and not the less expensive to run induction hob, reason its less expensive is efficiency so on for less time, but in the end everything will be electricity powered whether we have the infrastructure or not.

 

[paulrbarnard]

Just fitted a new induction hob and it has no provision for clamps, just a silicone mastic seal between the hob and worktop, difficult to believe, but induction hobs have better control than gas.

I was surprised by that too. I fitted an induction hob for my daughter and it is just held in by spring clips on the edges. Nothing hooking under the worktop. It seems very secure though.

It was also very thin so no cutting out of the cabinet underneath. A very simple installation.

 

[Distinterior]

.....It was also very thin so no cutting out of the cabinet underneath. A very simple installation.

That is unusual for an Induction Hob!.....They are normally about 50/55mm in thickness and require a couple of mm clearance between the bottom of them and the separator panel above the drawer below ( if there is a drawer fitted, that is.....)

Did she have thicker than normal worktops...?

There are now lower power Induction Hobs available that can be safely plugged straight in via a normal 3 pin 13A plug and I believe they are thinner in their profile, but obviously, they are slower than the higher powered options.

 

[John Brown]

I can only assume you have a halogen hob and not the less expensive to run induction hob, reason its less expensive is efficiency so on for less time, but in the end everything will be electricity powered whether we have the infrastructure or not.

No, it's deffo induction, and yes, I know they are more efficient, but still more expensive than gas, owing to electricity being 3 times dearer. Induction hobs aren't magic, like heat pumps, with notional efficiencies of 300 or 400%, as I understand things they're still resistive heating at the end of the day, just highly targeted resistive heating. A halogen hob wouldn't have the same grandchildren(and old fart grandfather) safety benefits.
None of which helps the OP...

Ah! It's just dawned on me that you thought I was saying induction was more expensive to run than other electrical hobs! We switched to induction from gas.

 

[paulrbarnard]

That is unusual for an Induction Hob!.....They are normally about 50/55mm in thickness and require a couple of mm clearance between the bottom of them and the separator panel above the drawer below ( if there is a drawer fitted, that is.....)

Did she have thicker than normal worktops...?

There are now lower power Induction Hobs available that can be safely plugged straight in via a normal 3 pin 13A plug and I believe they are thinner in their profile, but obviously, they are slower than the higher powered options.

You can get full power ones down to 12mm now. The one I installed was about 30mm and it went in to a 40mm top.