How to modify kitchen cabinetry for new oven?

[coastie]

Hi there

I bought an old place and moved in to find the oven didn't work. It was an old Chef Integra Baroness that had a separate grill. I have a new standard 60cm oven ready to install but does not have a grill and is a bit wider so I need to modify the cabinet. I've not done this kind of thing before but don't really have the spare cash to spend on a cabinet make, plus the kitchen is old and tired so it doesn't need to look incredible.

The current cavity is 765 wide 960 high and 589 deep (rear face of front panel to wall)

The current opening is 545 wide 905 high and 16 deep

The new oven requires a hole 560+8 wide, 590 high and 550 min deep. I want to modify the cabinet and add an off-the-shelf drawer underneath. I have some questions interlaced in the steps I plan to take below. Appreciate any help.

1) I will widen the opening to 560mm by taking off around 7.5mm each side of the opening using a jigsaw, I will clam some straight timber to use as a guide for a straight line.

I need to reduce the height of the opening by 905-590 = 315mm. 

2) I will need a shelf. The plan dimensions will need to be 765 wide (I might make it 760 wide to ensure it fits) and min 550 deep. Since the cavity is 589 deep, I'll go with 560 for a 29mm gap behind. Question: What material and thickness of that material should the shelf be for strength and any requirements for oven heat resistance? The shelf will be supported on two sides only.

3) Supports for the shelf. I want to narrow the cavity below the oven to 560mm to be flush with the opening and to fit an off-the-shelf drawer such as the one in this link

https://www.catch.com.au/product/elite-kitchen-pull-out-drawer-suits-600mm-cabinet-9115728/

I would then need to source supports for the shelf that are 560 long (to match the shelf) and each 100mm wide (from 102.5mm). The height of the supports would depend on the thickness of the shelf. For example if the shelf were 16mm thick, the height would be 300mm

Ideas for these supports would be appreciated.

In summary 

1) What thickness and material shelf would i need to support a standard 60cm Bosch walloven considering any heat requirements. If will be support on the sides with a span of about 560mm.

2) Ideas for the support that are 100mmx300mm (approx) cross section and 560mm long. Assuming that I can get a timber section a bunnings of these dimensions cut to length? What wood would I want? 

3) Anything I haven't considered?

Thanks for any help!

Pic below.  

[JacobZ]

Hi @coastie,

Thank you for your questions about modifying the kitchen cabinets to fit a new oven and welcome to the Bunnings Workshop community, it is great to have you with us.

Apologies for the delay in replying.

Some things you will need to take into account are the clearance requirements around the oven to allow for ventilation, whether the materials need to be fire rated and whether the oven needs to be installed by a licenced electrician. 

These requirements for installation will all be set out in the manufacturer's installation guide. I am wary to give advice as it would need to be in line with the requirements for your specific model of oven.

My suggestion would be to contact the manufacturer for their advice on what they require for a warrantable install of your oven.

Once we have the requirements for setbacks from cabinetry and required air gaps, we'll be much better informed an able to provide guidance.

If you have any other questions, please don't hesitate to ask.

Jacob

[coastie]

Hi Jacob

Thank you for your response. I have assessed in accordance with the installation instructions in the manual and my intentions meet all required clearances.

For support, the manual does not address the mass of the oven and thus support weight requirements. It states that a resistance of 90 degrees celsius is required from a heat perspective. I intend to have the oven installed by a licensed electrician, but want him in and out, installing the oven onto a pre-prepared cabinet that is ready to receive the oven.

I just need to know the material and thickness of shelf to meet the requirements based on being supported on two opposite sides only (which I presume most are since there is always a ventilation requirement at the rear edge) spanning 765mm wide. I also wanted ideas for support of the shelf but I will just go with the 2x100x300 timbers and shims to make up any additional thickness if no other ideas are thrown my way.

[MitchellMc]

Hi @coastie,

Typically, ovens are not installed directly on shelves; they utilise runners on the sides of the cabinet. This allows an air gap under the oven. If you take a look at our Kaboodle oven base cabinets,⁠⁠⁠⁠⁠⁠⁠ you'll see the chipboard runners that the oven sits on. Timber ignition points are generally over 200 degrees Celsius, but sustained periods of 90 degrees would not be recommended. If your oven requires a shelf that can cope with up to 90 degrees Celsius, that basically rules out most timbers like chipboard, especially melamine coated, and you'd need to look towards a more heat-resistant material, such as compressed fibre cement.  Consideration still needs to be given to whether an airgap would be required under the fibre cement. Keep this in mind for the sides and top of the oven if the melamine is in close proximity and will see similar temperatures.

Was there any provision for raising the oven off the shelf with timber rails on either side, or does it have to be fully supported by the shelf?

I suggest discussing your options with a carpenter or, ideally, a cabinet maker to ensure the materials used comply with specifications. Or, you might like to check whether the oven can be supported on rails, which would be the much simpler solution. 

Please let me know if you have any questions.

Mitchell

[coastie]

Hi Mitchell

There is nothing in the manual about rails. The model is a HBF113BR0A. 

User manual and installation instructions HBF113BR0A | Bosch (bosch-home.com)

Nothing depicted below either. As you can see from the original picture there were no rails on for my original oven either.

I will of course get an electrician to install the oven, I had just wanted to get the cabinet ready (DIY) before the electrician comes over. I didn't envisage this being so difficult as in my experience when people buy ovens I've never seen an assessment done of the existing cabinetry / materials in the kitchen, they just check the dimensions are compatible in store and bring it over to install. 

It looks like I'll be employing a cabinet maker.

Thanks
Coastie

[EricL]

Hi @coastie 

I believe that engaging the services of a cabinet maker is the safest course of action. You should still be able to tell the cabinet maker to install your drawer in the configuration that you like. It will be done to code and installed professionally. The best part is that it will all be under warranty.     

If you need further assistance, please let us know.

Eric

[Currawong64]

Hi Eric

i don’t feel this kind of answer is all that satisfying.  Building a cabinet is not a licensed trade and the knowledge not really the secret squirrel stuff of a licensed or specialised trade.

Yes the cabinet must meet or exceed the manufacturer’s requirements and should be followed closely.  I’m in the same situation with Bosch wall oven with exactly the same installation instructions, replacing an old Chef oven/grille combo that were common in the 1990s but has done its dash, leaving a larger hole cut out than what the new oven needs (by about 30mm).  

The good news is that the existing wall cabinet is totally sound with the correct ventilation space at the back.  The problem for me is a need to:

1/ remove and replace / install over or somehow reduce the front chipboard panel fascia of the oven cabinet by about 30mm on all 4 sides to suit the dimensions posted above.

2/ install a shelf & box for a microwave.

Would love to receive some suggestions here.  It’s really nice engaging with cabinetmakers who no doubt could do a great job. 

Doing so sounds nice & easy, but a little costly & takes away people’s DIY agency to far too great an extent I’d argue - some of us also have very tight budgets and really the project should not be overly complicated with customers feeling scared off by the recommendation of only hiring a cabinetmaker and paying the extra labour and tax.  It probably undermine’s people’s capacity to feel good and develop skills they didn’t know they had - so there’s a psychological payoff that’s not often articulated but exists.  Far too much interdependency and outsourcing goes on already in this world.

Further, Bunnings ought to be about championing DIY where it’s feasible and doesn’t involve licensed trades that of course need to be engaged - and as the previous poster remarked - to ‘get in & out’ (to minimise cost and dependence on professionals that must be engaged).  

Another option - simply measure and have a new cabinet fabricated by a local supplier and brought to site.  Truth be told this is probably what most cabinetmakers might do - to minimise onsite labour & maximise the comparative advantage of an at-scale fabrication business.  This second option is also nice - though the requirement for me like the previous poster - hang onto what’s still good and try to carry out a simple modification to it. Eg the right to repair!!

Also, it’s wasteful to just chuck out the whole old oven caninet which for all intents & purposes is quite sound - I could measure to have a local fabrication company make just my microwave box I guess (I say box as the rear must remain open at least 20mm all the way up the oven caninet for ventilation, out behind the microwave box)*.

Anyhow, my key question is whether there’s any suggested way to reduce the size of the front fascia to fit the smaller oven.  Perhaps I can try to pry it loose and replace it with a new fascia with a smaller cut-out.  Then install a box above it for the microwave.  Most materials appear not to be fire rated - just standard chipboard type materials - which appears to be fine - provided adequate ventilation & dimensions are observed in the new oven’s installation manual.  

If there’s a suggested solution, happy to hear about it.  

*microwave box - sits above the oven space - and also has a back panel that is open at the top for rear ventilation through the front and up out the back - but doesn’t at the same time occlude the min. 20mm space needed for the oven’s ventilation from the cabinet below.  The back of the microwave box is sealed from the bottom of the box upwards, so it can ventilate but there is no way for objects (potentially combustible) to fall down from the microwave box space or anything that’s above that (usually a high cupboard) from falling down into the oven space between the cabinet /wall / oven where air gaps need to be maintained.

Cheers.

[MitchellMc]

Welcome to the Bunnings Workshop community @Currawong64. 

It's great to see your enthusiasm for D.I.Y. projects and your commitment to making modifications on a budget. However, in situations involving potential fire hazards, such as modifying cabinetry around an oven, the risks are significantly high if not done correctly.

Ensuring the oven is installed according to the manufacturer's specifications is crucial for safety. In cases like these, it is highly recommended to consult a professional to avoid any potential dangers. Your safety is paramount, and while D.I.Y. projects can be fulfilling, some tasks are better handled by experts to ensure everything is up to standard.

Regarding your project, you might like to share some images so our helpful members can better understand what you're hoping to achieve. Let me know if you need a hand uploading pictures. 

Creating a frame for your oven would be possible by taking a larger melamine sheet and creating a cut-out in the middle to suit the oven. The sheet can then be cut down to suit the area. Kind of like a faceplate that covers the 30mm gap around the oven. You might even be able to add the faceplate over the existing one without removing it.

Please let me know if you have any questions.

Mitchell