I used a heat cable for years zip tied to hardwire cloth, wooden box with thick styro on the bottom, layer of sand, then the cable/cloth and soiless mix on top of that. Most seeds were up in 2-3 days in the unheated basement. All was fine till last season my new kitties decided this prop box was a great litter box. So now I have switched over to a heavy duty heat mat with wire cage in a wood box for 2 flat starts. I haven't bought the thermostat yet until I do temp trials. So far the lights with mylar and plastic over are keeping the soil temps at 72 but dip to 58 at night, so I will put a timer on the heat mat for when the lights are not running and test those temps. I had the lisianthus start to pop up in 6 days using this box.

Hi SandiB This is my first time over here at Garden experiments and your "hot tips for gutter cables" caught my eye. I have a wnderfully simple system that I designed for my cold frames. The heating cables that I use on the floor are similiar to gutter cables ,but they are the type used to wrap water pipes. Same principal just a little diff. application. The cable itself is 25feet long and is 10 watts /foot. The frames are 8'long x 4'wide. About 3 1/2 feet high in the back and 1 1/2 feet in the front. A pretty good pitch. 250 watts is plenty for my application. The wiring is relatively simple so I hope I don't turn it into a "challenge" while trying to explain it. On the back wall of the cold frame I mounted 2 separate electrical boxes which are connected by a short piece of conduit.In the upper box I have a standard line voltage thermostat which is wired to and controls a recepticle (weatherproof) mounted in the lower box. When the temp drops below whatever I have the thermostat set for, it will send power to the recept in which the heat cable is plugged into. Also the power comes to the coldframe from a heavy duty rubber cord which I plug int the back of the house. I don't use it during the coldest winter months for vegs. I put my seedlings out at the end of march/ beg.of April, and its looking more like April for this yr. I usually like (so do they) to start my seeds indoors and then move them out when they get their true leaves. It's a really a simple system and it works well. I'm much anticipating that 1st peep out of the tiny spring peepers. They will probably stay quiet until June, at the rate things are warming up. Do you have the gutter cables, or are you going to purchase in the future. If you dont have them yet, you might consider the type for water pipes. Just a thought. Joe in PA.

I would peel up whatever vinyl sheets are there. Then scrape the rest with a scraper. Tile needs a good substrate or the tile could crack, your grout break up, or tiles become loose. I would use something like Schluter-DITRA (Mike Holmes uses it constantly) orange waffle. I used a blue mat I found in the tile section of HD. It's intended to quiet tile for upstairs flooring, but it had a sticky tar like backing that made it ideal for laying over old laminate that wouldn't come up. Here is a link that might be useful: Schluter-DITRA orange waffle

If I'm working over a natural stone floor like marble that could be damaged by demo and/or construction within the room; building and installing cabinets, trim work, plumbing fixtures installed, walking over that floor to scratch-build a shower, etc, I'll cover the marble with sheets of 1/2" homosote. Homasote is a sort of soft cellulose product, comes in 4' by 8' sheets. I'll hold grit and take a ding. I have sheets of it I've been using and reusing for maybe 15 years. If the floor is not installed, I'll opt to install it last. With marble, it may be a good idea so seal the tiles prior to installation, then install, grout, and seal again. Master bathrooms, which are generally only trod upon by barefoot or slippered/socked adult feet, may not need multiple coats of sealer. Basic rules for marble installation? Your floor needs to be stiffer than a standard floor. Generally l/720 versus a minimum of l/360. If you can't achieve that, and maybe even if you can, consider a membrane like Ditra and installing the marble over that. Use a white thinset. Etc, etc. Since your area is pretty much done, you could set the marble. Seal it. Protect it. Then finish the remainder of the room. Personally, I prefer to set marble last. Set, grout, seal, run.