I live in a mansion that was built in the 1800's and about fifteen years ago was renovated. This building is also used for conferences and weddings on the weekend. None of the guys on the crews remember joist sizes or spacing. Sure enough, when I mentioned this to one of the carpenter crews one of them said, "Well shoot, Franny if you've got too much weight up there the floor cavin'in ain't gonna happen overnight. It's gonna happen when your're sleepin'one night, then boom! Geez! How do I figure out what the capabilities of the flooring is if one room where I have the tanks in is carpeted and the other room is covered with linoleum? Let me tell you what I have. In the living room: I have two 20 gal high tanks on wrought iron stands sitting on individual pieces of 3/4 inch plywood. Both of these tanks have 10 gals underneath. The tanks all have gravel. Next to these tanks are four 2.5 gal bare bottoms on a cabinet. Next to that is the 30 gal with the 20 long underneath. These tanks are all on the same outside wall. This room measures 14 x 11 with the usual tv and stereo, coffee table, sofa and chair. The kitchen has 4 10 gal tanks, 1 5 gal and a 2.5 on a stand I built out of 4 x 4's for legs and 2x 4,s for the shelving. The kitchen is 14 x 17 with table and chairs with cabinets. Does anyone have an opinion on load weight capacities Francine in MD Fish - photography - genealogy Francine, The floor finish makes no difference in calculating live load capacity of the structure. Most modern codes would require that a residential structure be designed for 40 PSF minimum live load capacity (80 PSF for corridors and 100 PSF for public areas, typically). There is no real way of knowing what your old house was designed for. In most cases, older homes have beefier structures, if they have been well maintained. Let's look at what you've got. In the living room: 120 gallons x (8 pounds per gallon of water + 2 pounds per gallon for misc. stands and gravel) = 1,200 pounds (a rough guess). In the kitchen: 47.5 gallons = 475 pounds. A wild guess at the footprints for these might be 10 square feet in the living room and maybe 4 SF for the kitchen. You can see that you are well over what the floor was designed for. You should probably distribute the load over a larger area than you've described. The most important thing to consider in your case isn't just that the tanks are against a wall but which direction the floor joists are running. If the joists are perpendicular to the wall, you are in much better shape than if the are parallel to it. The idea is to spread the load across as many of the floor joists as possible and to keep the load away from the middle of the joist span. You may want to consult someone with some architectural/construction experience to determine which way your joists run if it's not apparent to you. Sitting here, I can't say for sure whether you're ok or not. Hopefully though, this gives you some guidelines for improving you layout. A Lurking Architect ------------------------------------------------------------------------- This is the apistogramma mailing list, email@example.com. For instructions on how to subscribe or unsubscribe or get help, email firstname.lastname@example.org. Search http://altavista.digital.com for "Apistogramma Mailing List Archives"!