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Sagging 3/4" exterior grade plywood countertop base

Sagging 3/4" exterior grade plywood countertop base


  #1  
Old 01-01-02, 03:09 PM
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Unhappy Sagging 3/4" exterior grade plywood countertop base

We used 3/4" exterior grade plywood for the countertop base for a 36" wide peninsula. The cabinet underneath is 13.5" wide, which allows for seating on both sides. We doubled the thickness of the area which extends beyond the cabinet by screwing pieces to the underside of the top layer. I then installed 12" ceramic tiles. I have not yet applied the grout. After a few days we find that the plywood is sagging, in spite of the reinforcement. I have purchased heavy L brackets, but need to raise the plywood back to its original position. Am thinking of wetting the plywood in the grout lines; then using a jack to slowly raise each side. Any ideas/suggestions will be appreciated.
 
  #2  
Old 01-05-02, 12:17 AM
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I had to sit and think for a while to envision what you had created. 20/20 Hind site tells me you didn't use really good FIR plywood. Your island is drooping? L-brackets will help but you might try reengineering your project. If you could incorporate runners underneath and then add a nice "skirt" around the perimeter, you might end up with a better result. THe runners would act as supports for you counter top (running width-wise). They would have to run full width, you can't just add them on the sides...
IF the tiles are bending the plywood wait untill you try eating on it...
Do you have kids... they'll sit on it , lean on it , jump off of it...
(if you have kids you know what I mean, if you don't ... think drunk midgets).
If you jack up the sides will the whole top come loose?
If you get the top off couldn't you add another sheet of plywood?
Sorry I'm not much help but at least I got you thinking...

REDDOG
 
  #3  
Old 01-05-02, 06:48 PM
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Your observations and ideas are great! Thanks for taking the time to try to help. This has been my project with help from my husband, but this particular day husband AND brother-in-law took over. The plywood we used was Georgia Pacific; the best grade Lowe's had to offer. I didn't understand their idea of adding pieces on the bottom. Seemed logical to me that would simply add weight, so I wasn't particularly surprised to see the drooping. I just think there is too much weight with tiles on top and chunks of plywood fastened to the bottom, and too little support with the "supporting" cabinet falling in line with the grount lines. Rather than raise the top and add to the height of the work surface, I've decided to first try my original idea; attempting to return the wood to a level surface; then reinforcing with heavy angle irons. In addition, we'll add sturdy legs to the outside corners. Not only should this provide additional support, but will hopefully prevent one of our five grandchildren from plowing into the cantilevered top as they perform their constant high-speed run around our circular traffic pattern! We had three of them over for the weekend, and I can't believe we didn't have to make a run to the ER!

Should my plan NOT succeed, I'd love to know what material you would use to create the "runners".

Thanks again for your brain power.

Grammy Z
 
  #4  
Old 01-05-02, 09:35 PM
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I'm not trying to intrude on your idea but instead of heavy legs going straight to the floor would supports coming from the island bottom and running to the counter top look better.... I didn't explain that very well did I... on an angle from the outside corners to the floor where the island is... like legs but angled in, so you don't stub your toes. For "runners" I would try angle iron... but not with a flat surface mounted to the countertop... I would install it so it resembled a "V" . This is stronger and it protrudes less ... then I would install a one inch or two inch skirt around the bottom made of oak or pine or whatever fits. Speaking of wood when I talked about plywood I meant the type of tree used in making it ... not the grade. Constuction materials such as siding aren't usually made of FIR but rather pine... pick up a sheet of pine and then pick up a sheet of fir ... its heavy and solid ... regardless it would probably bend too. One layer of plywood isn't enough support for what you have in mind. I hope your shelf bracket idea works ... I know its 36" wide but how long is it? 8feet? just wondering

I hope it works out for you Grammy Z

REDDOG
 
  #5  
Old 01-06-02, 04:52 PM
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Wish I'd known we were going to have so much trouble. . . I'd have contacted you first! I'm so tired of the remodeling, holidays, post-holiday activities, yadda, yadda, yadda, that I've let it go for a while. Put up shelving for toys in the guest room closet. Six year old and four year old "helped" with the painting. Went off without a hitch and was a fun project for us all. Thanks again for all your suggestions on my kitchen dilema. Hope I can send a photo of the finished project (which is 7 feet long).

Later,

Grammy Z.
 
  #6  
Old 01-06-02, 04:54 PM
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Wish I'd known we were going to have so much trouble. . . I'd have contacted you first! I'm so tired of the remodeling, holidays, post-holiday activities, yadda, yadda, yadda, that I've let it go for a while. Put up shelving for toys in the guest room closet. Six year old and four year old "helped" with the painting. Went off without a hitch and was a fun project for us all. Thanks again for all your suggestions on my kitchen dilema. Hope I can send a photo of the finished project.

Later,

Grammy Z.
 
  #7  
Old 01-06-02, 05:03 PM
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Wink

I'll look forward to seeing that.

REDDOG
 
 

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