This is a 48'x80' shed that I am building. I am just using it to give you a visual idea of what you could do with the existing pad. If you wish to use the pad but make the shed larger than 6x10. Say 10x12 for example. Dig down below the surface of the outer edges of the pad (much like digging a ditch) to the desired size. Measure and set the post to the size shed you want. On the bottom outside of the post nail 2X's (4,6 etc) so that they are level with the pad. Then fill the void with gravel base and then concrete to make the entire pad level. Build the shed. You can go back later and paint the pad which is now your floor to make the finish even between old and new construction. Once I have the roof finished on my shed. I will go back and remove the grass and run a compactor over the surface. Lay a bed of compacted gravel over that. Then nail 2"x6"'s level around the outside of the post. and pour the concrete using them as forms. The yellow triangles are to show how this will be done. This does a few things. It allows me to drill the post and run rebar rods through them to covered with concrete. Makes the walls even with the outside stringer. Places the siding out away from the concrete pad 1 1/2" for drainage (stringer will be even with the pad making it weather proof). Adds another 6 inches of support to the corner post on two sides and three on the side wall post. Just an Idea of my way of building sheds for you to consider.

Length, width and height. This isn't cast iron, we're looking at porcelain-enamel over steel. I'm finding very few 30x60 tubs unless I'm willing to sacrifice height. Taller (standard) tubs with higher water levels are about 32". My concern (and need to post here) came from an online plumbing supply store that stated the following: Product Specifications: Overall Length: 60" (head-to-toe measurement when lying inside the tub) Overall Width: 32" (shoulder-to-shoulder measurement when lying inside the tub) Overall Height: 17-3/4" (exterior height from base structural support to top of tub lip) Water Depth: 14" (height from tub floor drain to overflow outlet) Maximum Water Capacity: 50-gallons. The pdf led me to a completely different tub (a whirlpool tub). "Overall" length is described as "head-to-toe measurement when lying inside the tub"...Really! :o They messed up.

I suppose you could Redguard it and tile away. Nothing ventured, nothing gained. Personally, I would rebuild it....but you say that's not an option. We really don't know if there is a vinyl/rubber liner under the mudbed...nor do you, apparently....and a redguard membrane, if that is the case, is superfluous. At this point, just paint the stuff on and tile away. It may last awhile...it may last forever. You pays your money and you takes your chances....

They were super nice and accomodating when I sent in a request through their contact form with my questions. I didn't know they made 96" panels, had a corner seat, or bigger niche with a shelf until I asked. Also providing a "remodelers" trim that allows you to put the panels over existing tile is a huge bonus if you don't want to do a tile tearout. I think they thought of everything so wouldn't be surprised if they do your dual threshold. They sent me the following details on order fulfillment and shipping: "Once an order is placed, it will take 2-3 business days to fabricate and 2-3 business in transit from our Utah factory to get to Denver. The materials are fairly sizable, so they will be strapped to a large pallet and sent on a truck as an LTL shipment. The carrier will call you before making the delivery. They will arrange an appointment with you to make the delivery. You will need to be home to receive the delivery. They will drop the pallet at your front door or in your garage." Made in the USA is a huge plus so there is no delay. Also when I called to place the order we talked to the guy and asked about what aspects people had trouble with on installation and he walked us through his tips and suggestions. We had already watched all their on-line installation videos and read the instructions. Everything seemed doable and was well described.