Not happening without some substantial reinforcement. Frameless cabinets sides are everything when it comes to structural integrity and counter support. Cutting the sides voids any warranties, and risks them collapsing without alternative engineering supports.

You will have to build interior support which can be done and then skinned or build a cab and face it with Ikea material. This is a doable hack, I think...but the question is what would be the best way. Personally, I would try hacking two 24” cabs with added interior supports and then skin the inside to hide the support.

This might give some ideas:

https://www.ikeahackers.net/2014/02/farmhouse-sink-into-ikea-kitchen-cupboards.html

I think it will be doable. I found this blog post about a similar project.

It doesn't need to be quite this beefy, because the sink itself weighs less than half the amount of the one in the blog post.

https://www.ikeahackers.net/2014/02/farmhouse-sink-into-ikea-kitchen-cupboards.html

I'm assembling the cabinets (and doing any modifications to them like this), but installation, plumbing, templating and cutting of countertops, etc are all being handled by professionals.

Now, I mostly need to find out about additional sink support options (straps, brackets, etc) and see if a revised layout makes sense in our space.

I combined two cabinets to support my 48” range top, so it’s definitely doable. We had the benefit of being able to essentially add a “top” to secure them together, and that was the vast majority of the support we needed.

You don’t *need* a shelf to set the sink on (like we did), but it may be easier to engineer it that way, even if you don’t use the shelf.

Hello Ted, Did you end up using an Ikea cabinet for a 45” sink? What did you do for the base and support? what about the cabinet face? Thanks!

@memsony - We did end up using Ikea cabinets for the 45" sink. We did a pair of 24" cabinets so the front is just regular cabinet doors... we mounted them as pull outs. The interior side walls of the cabinets were notched to allow the sink to pass through.

We used an undermount sink suspension system that provides a continuous solid support underneath the sink from one side to the other. Three years in, we've had no issues and everything is holding up perfectly. I will try to find the link for the product we used for the undermount sink support.

Found it... this is the exact kit we have installed - though it may have been under a different name back then.

Undercount Kit

As I said. It has been rock solid. I chose this after looking at pretty much all the undermount support kits available in 2019 and it had performed perfectly.

We are in the same category with kitchen cabinet limitations!! Thank you so much for the follow-up that you were able to make two 24" cabinets work. I would really appreciate if you could share the link for the supports that you found for the 45" undermount sink!

Karyn - see my second comment above (right above your comment) the link is in there.

Thank you so much for your quick reply! The last comment above my comment, it says: We used an undermount sink suspension system that provides a continuous solid support underneath the sink from one side to the other. Three years in, we've had no issues and everything is holding up perfectly. I will try to find the link for the product we used for the undermount sink support." For some reason, the link did not make it into the discussion. Are you able to copy and paste it again or perhaps give me some pointers of where to search? Thanks again!!

Pete will make a custom sink mount kit.

Hi Karyn, I'm not sure why you couldn't see my other comment (I made that one just a minute or two after I posted the one you referenced)... but here is the link. Hopefully this works

https://www.amazon.com/Native-Trails-UK2547-Large-Undermount/dp/B07DNSG2CD/ref=sr_1_1?crid=2QD70BLE2E978&keywords=native+trails+undermount+support&qid=1658226569&sprefix=native+trails+undermount+support%2Caps%2C44&sr=8-1

@Ted and Kathy Howe thank you so much for sharing the informain. glad to hear the kitchen turned out well!

@Ted and Kathy Howe Thank you so much for responding with the link - I can see it now! After much research, I found that although my cabinet manufacturer does not make a 48" sink base, they do make a 48" vanity. I spoke with my builder and he can create a workaround the 21" depth as a solution to make my 45" sink a reality! I am very appreciative of the time that you took to share the details of your success story with us.