[jplee3]

Hey guys,

Working on installing a new over range microwave and have to get a filler block in since there's overhang in the front.

Is a 3"x3" or 4"x4" block enough? I have some short 2x4 pieces I can cut up but I still need to fill 1/4" gap... I found an old cedar moth-repellent hanger where the hanger piece broke off leaving a small 'shim' of cedar - is it OK to use this to shim that space? I know cedar is soft wood and usually not recommended for supporting heavy weight so not sure.

The other question I have is if I need to secure the filler block to the bottom of the cabinet shelf before drilling the hole for the bolt. Or if the filler blocks can be 'loose' and just have the hole pre-drilled... I'd imagine it might be tough lining all the holes up though when going to secure the microwave?

 

[Nealtw]

are the gaps above, beside or behind it?

 

[jplee3]

are the gaps above, beside or behind it?

The gaps are above - there's a cabinet with a front overhang above where the microwave is to go. The gap is right at 2-7/8" - the 2x4 would leave a slight gap in which case the cedar would mostly fill it out.

 

[Nealtw]

The gaps are above - there's a cabinet with a front overhang above where the microwave is to go. The gap is right at 2-7/8" - the 2x4 would leave a slight gap in which case the cedar would mostly fill it out.

Will you still have the required height above the range. Might be 18"?
The 2x4 blocks screwed from the cupboard beside it would be good.
I would just add a piece of 1/4" plywood below that.

The screws down from above will not be long enough so you will have to deal with that.

Connecting the exhaust vent could be trouble some if you are going out the top.

I did one where the shelf above was a mess as it had previously had an 8" round thru it, so after it was all hooked up I put a piece of white shelving in on top to clean it up.

 

[jplee3]

Will you still have the required height above the range. Might be 18"?
The 2x4 blocks screwed from the cupboard beside it would be good.
I would just add a piece of 1/4" plywood below that.

The screws down from above will not be long enough so you will have to deal with that.

Connecting the exhaust vent could be trouble some if you are going out the top.

I did one where the shelf above was a mess as it had previously had an 8" round thru it, so after it was all hooked up I put a piece of white shelving in on top to clean it up.

Thanks. There are two bolts that came with the microwave that I think will be long enough - they're at least 3-4" long.

With old range hood up:

After removing the range hood

Installed bracket, removed old shims and drilled holes for the top bolts (hope they match up to the microwave!!!). So the cedar plank I have, if I were to just slide that and sandwich that between the piece of 2x4, would that be OK? I'm thinking of cutting just a small 3" x 3" or 4"x4" square of the 2x4 and cedar (or whatever I can find that's better to shim the 1/4" of space). I may just use a couple wood screws or nails to connect the shim to the 2x4 block and then wood screws to help secure the blocks/shims to the cabinet bottom. I don't think I need a huge piece of wood to fill that gap - it's literally just a small filler block to fill the gap. Although now that I think about it, I suppose it would add support if I were to use a length of 2x4 and 1/4" shim that runs from front to back right? Similar to this one (which was used to support the range hood (unfortunately, I couldn't retrofit it to the microwave as the bolt hole locations on the microwave are literally an inch off from where the old supporting block/shim was:

In terms of the venting - it is going to be a pain - the location of the exhaust vent is off to the side at a 30 degree angle from where the venting would come off of the microwave. I had to buy a boot adapter from the microwave to the 7" diameter venting and picked up a roll of aluminum tape too. That's definitely going to be a puzzle figuring out

 

[jplee3]

Here are pics of the progress up until now:

This is the block and shim I'm referring to: 2x4 is on the top and the cedar shim is below it. It's right up against one of the bolts (to secure the top of the microwave) just for reference - if I were to actually use these I would cut them smaller (to 3x3" or 4x4" squares), drill a hole for the bolt to pass through and then secure them together and to the cabinet bottom as I had described earlier:

Would it be better to use an entire length of 2x4 and same length shim to create a "beam" for more support? Or am I already getting plenty of support from the bracket on the wall combined with the two top bolts? I'm thinking this approach of using a longer length/beam is somewhat overkill. And I'm also thinking that that cedar shim might be just fine - what I may do is sandwich it between the cabinet bottom and 2x4 (so just reverse the way I have them stacked in the picture). I think the "filler block" was solely meant to prevent damage to the microwave top and the bolt 'pulling' the microwave top and potentially warping it - so the filler block would 'pad' that. I suppose it acts as extra support/security too but not sure how much load it's actually bearing.

Thoughts?

 

[Nealtw]

Here are pics of the progress up until now:





This is the block and shim I'm referring to: 2x4 is on the top and the cedar shim is below it. It's right up against one of the bolts (to secure the top of the microwave) just for reference - if I were to actually use these I would cut them smaller (to 3x3" or 4x4" squares), drill a hole for the bolt to pass through and then secure them together and to the cabinet bottom as I had described earlier:


Would it be better to use an entire length of 2x4 and same length shim to create a "beam" for more support? Or am I already getting plenty of support from the bracket on the wall combined with the two top bolts? I'm thinking this approach of using a longer length/beam is somewhat overkill. And I'm also thinking that that cedar shim might be just fine - what I may do is sandwich it between the cabinet bottom and 2x4 (so just reverse the way I have them stacked in the picture). I think the "filler block" was solely meant to prevent damage to the microwave top and the bolt 'pulling' the microwave top and potentially warping it - so the filler block would 'pad' that. I suppose it acts as extra support/security too but not sure how much load it's actually bearing.

Thoughts?

You don't need any blocks the bolts will just pull it up tight under the front of the cupboard.

I don't like the shelf as it is just nailed up so it could pull down in the back

you could put a 1x2 under it for extra support and a 1x2 on each side level with the bottom of the front so the MW pulls up tight there too.



With that round duct, I just got an adapter to 4" so it was easier to deal with.
I think i had the adapter made something like this so it sat flush with the wall with a 4" hole in the middle.

 

[jplee3]

You don't need any blocks the bolts will just pull it up tight under the front of the cupboard.

I don't like the shelf as it is just nailed up so it could pull down in the back

you could put a 1x2 under it for extra support and a 1x2 on each side level with the bottom of the front so the MW pulls up tight there too.



With that round duct, I just got an adapter to 4" so it was easier to deal with.
I think i had the adapter made something like this so it sat flush with the wall with a 4" hole in the middle.

Ugh, I measured wrong - the gap is actual 1-7/8" (I said 2-7/8" earlier). So much for measuring correctly lol. So it sounds like what you're saying is to build a pseudo-frame around the remainder of the bottom cabinet (sides and back) to avoid dealing with a couple filler blocks as the bolts will 'pull' the microwave to hopefully sit flush against the cabinet with the additional "supporting frame"

Now that I think about it, I actually shouldn't have removed those existing supports that the range hood was bolted to!!! Dohhhh *facepalm*
Oh well, I guess it's a learning experience right?

 

[Nealtw]

Ugh, I measured wrong - the gap is actual 1-7/8" (I said 2-7/8" earlier). So much for measuring correctly lol. So it sounds like what you're saying is to build a pseudo-frame around the remainder of the bottom cabinet (sides and back) to avoid dealing with a couple filler blocks as the bolts will 'pull' the microwave to hopefully sit flush against the cabinet with the additional "supporting frame"

Now that I think about it, I actually shouldn't have removed those existing supports that the range hood was bolted to!!! Dohhhh *facepalm*
Oh well, I guess it's a learning experience right?

yes but put the back one up tight to the shelf, it needs help.

 

[jplee3]

yes but put the back one up tight to the shelf, it needs help.

So without taking trips to the hardware store, unless I can find a long enough length of 2x4 and .25" thick piece of MDF or plywood scrap, I think what I'll do is take a couple small pieces of the 2x4 with a matching sized piece of the cedar plank and screw those to the back of the cabinet as you say. Then at least there will be some support back there. Based on what you're saying, it seems like having *something* in the back will help with the weight distribution versus depending on the front frame and a filler block that's also towards the front of the microwave (where the bolt holes are). BTW: Is it better to secure/screw these blocks from the bottom up or top down?

 

[Nealtw]

So without taking trips to the hardware store, unless I can find a long enough length of 2x4 and .25" thick piece of MDF or plywood scrap, I think what I'll do is take a couple small pieces of the 2x4 with a matching sized piece of the cedar plank and screw those to the back of the cabinet as you say. Then at least there will be some support back there. Based on what you're saying, it seems like having *something* in the back will help with the weight distribution versus depending on the front frame and a filler block that's also towards the front of the microwave (where the bolt holes are). BTW: Is it better to secure/screw these blocks from the bottom up or top down?

No, I was concerned about the back of the shelf falling down. some bracket or something screwed to the wall under the shelf.

 

[huesmann]

Is the bottom of the cabinet at least ply or solid wood, not particleboard or MDF?

 

[jplee3]

No, I was concerned about the back of the shelf falling down. some bracket or something screwed to the wall under the shelf.

Is the bottom of the cabinet at least ply or solid wood, not particleboard or MDF?

The bottom of the cabinet appears to be particleboard - the shelving in these original cabinets are all particleboard unfortunately. However, the original shims that were in place were holding the vent up on it's own without additional bracket. I guess the microwave is going to weigh significantly more though right?

So would something like metal L-brackets help at all here? Or would solid would framing that Neal suggested all the way around be the best bet? I would still need to 'anchor' the solid wood 'framing' securely to the existing cabinetry though right?

I guess my other question is how much load the wall-bracket for this microwave actually bears, since that's the first thing the microwave is set on and it requires at least one of the screws holding it in place to be attached to a stud.

 

[huesmann]

The nuke box is likely to be significantly heavier. What I would do in this situation is get a couple pieces of flat 1" board and stick those in the bottom of the cabinet, below the shelf. Drive a couple nails or screws into the front face of the frame to secure the boards in front (since your cabinets appear to be painted, you could easily hide the nail holes). Use a couple of metal brackets on the back and secure to wall and bottom of board. Brackets will be hidden by the microwave. I would think that would provide the additional support you'll need.

 

[jplee3]

The nuke box is likely to be significantly heavier. What I would do in this situation is get a couple pieces of flat 1" board and stick those in the bottom of the cabinet, below the shelf. Drive a couple nails or screws into the front face of the frame to secure the boards in front (since your cabinets appear to be painted, you could easily hide the nail holes). Use a couple of metal brackets on the back and secure to wall and bottom of board. Brackets will be hidden by the microwave. I would think that would provide the additional support you'll need.

Thanks! I was just thinking about that while making coffee and looking over the situation. I was originally thinking about doing that with a couple lengths of 2x4 but I think that would be too much - there's actually a strip of wood supporting the back of the cabinet that the particleboard shelves are attached to in the back. I might be able to drive a couple screws up into that (trying to do that with a 1x6 versus a 2x4 would probably be easier).

BTW - if I did want to grab some metal brackets, how big of brackets should I get? My concern with that is that there's only one stud and it's almost in the middle (slightly off center) of this space. So even with brackets, it wouldn't really be secured to anything substantial unless I were to align the bracket with the stud somehow (the stud does not intersect with either of the bottom shelves though).

Here's what I was envisioning (brackets not factored in yet)

If brackets are still advisable, what size/type brackets should I consider?

 

[huesmann]

Actually, I just had a better idea. If you do have a stud somewhere, you could use a piece of steel or aluminum angle to support your 1x6 at the back of the wall. Just like the microwave mounting bracket, you would have at least one screw through a stud that way. It'd basically be a continuous bracket. You might have to notch out the top flange where your vent fan will exit. The metal angle wouldn't need to be that heavy duty; the microwave mount isn't that heavy duty.

 

[jplee3]

Actually, I just had a better idea. If you do have a stud somewhere, you could use a piece of steel or aluminum angle to support your 1x6 at the back of the wall. Just like the microwave mounting bracket, you would have at least one screw through a stud that way. It'd basically be a continuous bracket. You might have to notch out the top flange where your vent fan will exit. The metal angle wouldn't need to be that heavy duty; the microwave mount isn't that heavy duty.

So in my last post I indicated where the stud is in the picture w/ the caption - unfortunately it's almost smack-dab in the middle of the opening so there's no existing shelving there. It's basically behind where the venting needs to exit so I can't put a shelf there. In this case, there's a solid wood support 'beam' running across the back and the particleboard shelves are attached to that at the rear. It would be nice leveraging the stud for this part but I don't see how it's possible to, unless I'm missing something?

 

[huesmann]

Are you venting up or back?

 

[jplee3]

Are you venting up or back?

The vent is above -it's in a pretty awkward location but yea...

Basically the piece of foil you see in this pic and the last one from the other post are where the vent outlet is - I have to modify the ducting to run up there. The prior range hood was setup for this:

 

[Nealtw]

The bottom of the cabinet appears to be particleboard - the shelving in these original cabinets are all particleboard unfortunately. However, the original shims that were in place were holding the vent up on it's own without additional bracket. I guess the microwave is going to weigh significantly more though right?

So would something like metal L-brackets help at all here? Or would solid would framing that Neal suggested all the way around be the best bet? I would still need to 'anchor' the solid wood 'framing' securely to the existing cabinetry though right?

I guess my other question is how much load the wall-bracket for this microwave actually bears, since that's the first thing the microwave is set on and it requires at least one of the screws holding it in place to be attached to a stud.

The particle board is a good catch, you really need a 1x2 or 2x2 under the back screwed to the studs in the wall.