In this episode of my granite fitting saga, it appears that there won't be enough room for the 40mm wooden beam across the twin appliance gap to support the granite. What width steel box section would have the same bending resistance as the 40mm wood specified?
Also, can granite rest directly on the metal, or should there be a soft material on top, such as hardboard?
Christian.
I would suggest using something softish, or at least some silicone sealant to allow for small movement.
.andy
To email, substitute .nospam with .gl
Use 3mm walled box section, as thick as you can fit in there. 40mmx20mm would be plenty, but the thicker the better.
I'd want a cushion of silicone between the steel and the granite.
So 20mm high will be enough to stop the Granite cracking when the uninitiated decide to sit on the worktop? How many should I put across? I was thinking of one near the front and one in the middle. The rear will be held by some 2x3 softwood bolted to the wall.
I should just squeeze 20mm in. I've got around 45mm absolute tops to play with. 40mm would be safer, making it easier to insert/retract appliances and less likely to end in tears. I can't lift the worktop another mm without serious issues elsewhere.
I've got to get the beam, slate, tile adhesive and sealant in there then. I've already got the 12mm ply down, so don't need to account for that.
That gives:
Adhesive 3mm Slate 12mm Beam 20mm Sealant 5mm
That gives me exactly 40mm, so it should be OK, provided I spread adhesive carefully.
I take it I can just run a thick bed of sealant and let it dry? I don't think I want to glue the granite down? Is there a more suitable material for this anyway, such as laying thin MDF/hardboard over the entire space?
Christian.
[T] I think the issue here is that granite isn't very flexible and most other things are?
If you placed a length of your selected section on two blocks (same spacing as your cabinets) and pressed in the middle, I think you'd find pretty well anything will 'give'?
Is there any way you could fit a wall bolted, 'triangular' shaped, steel brace in the middle or do you need an uncluttered space?
All the best ..
T i m
p.s. My feelings about how much apparently rigid things bend has been enhanced since I have been using my 10 tonne hydraulic press. I gas-cut a couple of 20mm steel plates, 50cm x 25 cm to act as a bed for items on the press. The plates were a bit warped so I thought I'd have a go at bending them straight with the press. Raised the ends and pressed in the middle and they bend back easily .. (well, a couple of tonnes worth of 'easily') ;-)
I'd need to drill a very big hole through the washing machine to accommodate the brace. It might prevent the drum rotating, too.
Seriously, though. I've been told that a 40mm wooden beam across the front is sufficient. I just want to know if I can reduce this using a metal beam (or several) as I don't have 40mm to play with. There is absolutely no way that any part of the structure can extend more than 25mm below the bottom of the worktop over the 121cm span.
Christian.
[T] Ok, so it's 'doable' then ;-) [T] Sounds like the suppliers I know .. ;-) "Yes just hit it hard with a hammer .. it will be fine .... oh you did and it broke ... click .. brrrrrrrrrrrrrr "
I just want to know if I can reduce this using a metal beam
[T] I see ... theres no doubt that a piece of hard wood will help but would it be enough to prevent an expensive lump of slate / marble snapping in half if someone sits / climbs on there by mistake. You have see the large glass table tops being smashed on 'Youv'e been framed' when folk treat them the wrong way?(Like when my 'terrified of heights' friend went up the CN tower and the kids were jumping up and down on the glass floor some hundreds of feet above the ground ... I would be looking for stress fractures, loosse bolts, rust or maybe NOT walk over the glass sections at all (just in case).
I digress. Any decent section of steel would probably be stiffer than the same size wood. The deeper the 'wall' the stiffer the box, the problem is you would have to have it round the 'short' way.
I have some lengths of 50mm x 25mm x 1.5mm thick seam welded steel box left over from when I built the garage doors. It's pretty stiff (unlike angle) and probably stiffer than the support the cupboards can provide?
Sit the top on that with a couple of strips of 1mm thick double sided foam to provide the cushion and that's about the best you can do in the space?
I assume you wouldn't be able to take the box section along the entire length of the worktop (this would provide more support?)
All the best ..
T i m
Hmmm, I take it we are talking about this layout, from your thread "Granite worktop span"?
++----+----++----+---+----+---+---+ || WM | TD || DW | +----+ | | || | || | 1 |SINK| 2 | 3 | ++----+----++----+---+ +---+---+Support profile: ^^ 1.2m ^^ ^ ^ ^ ^ ^
You need a support 'twixt the WM and TD, yes? How about this (which is what I thought Tim meant but, judging by his reaction to your reply, it wasn't) fabricate a "shelf bracket" from angle iron and flat strip, it only needs to be 3mm thick steel, screw it _solidly_ to the wall at the back of the worktop. It will be more than strong enough. All you need is
3mm of space between the WM and TD, surely you must have that?I couldn't draw it in ASCII art, so here's a quick CAD drawing of what I mean.
25mm is, perhaps, a little too much, but pretty close. Although the instructions call for 40mm wooden beam across the front, I am hoping that doing several structs of metal 20mm will provide enough support.
No. The next item is the dishwasher, which must be flush against the worktop, unlike the washing machine and tumble dryer, which have the facility to bolt the doors artificially high to cover the gap. Between the dishwasher and tumble dryer is a stud framework with a pretty column pillar on the front. The studwork is made of 47mm x 75mm softwood, so should provide enough support for the metal lintels. I was planning to channel out about 30mm for the lintel footings with a router.
Christian.
Well, I've got a quote of 40 quid for enough 3/4" x 3/4" 16 gauge to span 3 times. That, I believe means 19mm x 19mm @ 1.5mm thick. Hopefully, this will be stiff enough to stop the Granite cracking. It also gives me space for a
5mm MDF sheet over the top, which should make the worktop fitting a bit easier. I will measure again carefully, in case I can fit the 1" stuff in.Christian.
[T] Hi Parish, it was exactly what I had in mind for the middle of the span but it turns out there is no space for such? I think Christian is going to use the surrounding gear for the xbeam support at either end?
It will be more than strong enough. All you need is
into a thin gap. If it was 3mm thick and as wide as your drawing suggests it shouldn't buckle under compression ;-)
All the best ..
T i m
[T] Ah, I see .. the reaon for the extended x bar is that it would be supported by the box that is being held down by the granite eith side of the span and helping to make the who lot 'stiffer' ?
All the best ..
T i m
p.s. I also have some (I think) 25 x 25 square box (like the Speedframe stuff used for knock together workbenches) or some 20 x 15 x 1.5mm ? Will they take 5m lengths in the post?
All the best ..
T i m
Yes, I can see that would improve matters considerably. Unfortunately, the dishwasher simply has to be next. Otherwise, the dishwasher would be next to the Belfast sink, giving a stainless steel side slightly on display and nothing to support the end of the granite section.
Hmmm. Approximately where in the country are you?
Christian.
Remind me - what's the span?
I wouldn't worry about gluing the granite down - it'll peel off easily enough.
I think I misread the original idea slightly, thinking of the bracket coming from another angle.
The main problem with this solution is that it is next to impossible to wiggle the washing machine in and out directly without borrowing the space from the adjacent tumble dryer, which is itself so light it pushes in and out with ease, giving the washing machine some room for manoevure.
If it is the only way to provide enough strength, then maybe I'll have to do it, though, and pay for washing machine repair men to overcome the installation/removal issues!
Do you think that 3 spans of 19mm box section would not be sufficient support? If not, would the 25mm push it into acceptable territoriy?
i.e.
+----------------------------- +-+-----------------------+-+- | | | | |###########################| | | | | |###########################| | | | | |###########################| +-+~~~~~~~~~~~~~~~~~~~~~~~+-++----+
+----+ = 47mm wide, 75mm tall softwood###### = 19mm box section stainless steel
~~~~~~ = decorative edged chipboard trim
Entire area inside of the softwood covered in thin MDF, flush with softwood surface.
Christian.
121 cm. Back edge and sides well supported.
Christian.
Then 20mm x40mm with 3mm wall will be fine - use 2 lengths - front and middle.
How often are you likely to need to pull the washing machine out? Not very I expect. If you were to fix a brace like this with the angle iron flanges on the TD side you could pull the TD out and remove the brace, then put it back after the WM has been repaired/replaced. surely the granite only needs supporting in case someone sits on it? It should support it's own weight easily over a 1200mm span?
The advantage of a brace like that is that you can make it as deep as you need to and making it totally rigid (for any conceivable load it's likely to be subjected to) would not present a problem.
Regards,
Parish
Obviously the 20mm is in the important vertical direction. Also, the metal companies seem keen of "16" gauge, which they suggest is 1.5mm, rather than
3mm. Is this well underspecced? Does anyone publish formulae?Christian.
I gathered that from your limited space.
I wouldn't use 1.5mm wall for this.
I think you'll find it difficult to get a calculation on this - because what you're aiming for is as close to zero deflection as possible. This isn't normally calculated for. There has to be a certain amount of gut feel/experience here. If you play around with some box section, you'll soon see what I mean.
3mm walled box is easy to get hold of.HomeOwnersHub website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.