Hi there... I actually "have" a mature woods in my backyard but it's in bad shape. It's an old farm woodlot that was clear cut at least twice. The trees are largely maple with some black cherry and American Beech but these guys are right, unless you like a "rough" walk through your woods, the roots are often above ground and somewhat hard to work around. In my case the woods had no understory at all save for a few species of spring ephemerals. Our project has been to build the woods an understory to fill in the huge gap between the floor and the canopy 70ft. above. I consulted the local conservation authority and they told me to give it up b/c "it's almost impossible". "Understory tree species and shrubs need to grow along WITH the canopy". Being the stubborn person I am, I didn't listen to them and have found many varieties to serve my purpose. I think at last count I've introduced about 44 native species. Do some reading, research the net and find species that you like but that also will grow alongside your canopy species and then still thrive once the canopy is better established. One understory shrub that works well in sun as well as shade is the Serviceberry. In sun the Serviceberry turns neon orange in autumn and puts on a fantastic show. In shade it grows just as well but the fall show is a little more subdued. The leaves tend to turn more golden and yellow with little splashes or hints of orange. Serviceberry has a very nice habit and doesn't mind you pruning it to produce an even more compact appearance. Another species that does well in both sun and shade is the Witch Hazel. I have one in full sun on my front lawn and one in full shade in my wooded area. Both are doing equally well and turn the same colour in autumn. Winterberry is a deciduous Holly that you can plant around the base of your trees now. It loses it's leaves in fall but bright red berries will remain through the winter and are a favourite with the birds. Once the canopy trees are established the winterberry will do even better in the shade. Winterberry need male and female plants to set fruit. "Nannyberry", "Arrowood Viburnum" and "Ninebark" will also do fine in both sun and shade situations. The Nannyberry and Arrowood have deep blue/black fruits that will drive the birds wild. American Cranberry" works nicely at the edge of your woodland design and the red/orange berries last well through the winter for the birds and look pretty against the winter snow (if you get snow that is). Check out some of the dogwoods that do ok in sun but thrive in shade. I'm not up on them but I think Grey Dogwood might be one (don't quote me on that though). Some dogwoods like only sun while others like only shade and a few fit in the middle but almost all will do fine as a forest edge species. A really lovely deciduous tree through all seasons is the Sweetgum. It is deciduous but has the same shape as a Christmas tree and leaves that are like a Japanese Maple. They grow quickly and the best part is the fall colour...it's spectacular and is a bit different every autumn. It can turn any colour from burgundy to scarlet red and some autumns it litterally appears on fire with colour. Nurseries often sell them pruned to look like a deciduous tree with a trunk and then the leaves at the top but their natural appearance is like a christmas tree, with branches coming out right from the bottom and forming a cyllindrical shape. Anyway, I think you should just do what makes you happy. Look up what species will work well in sun or shade, make natural looking "thickets" and use "natural succession" as a guide where to put things. The most fun we had with our little wooded area was planning the little pathways that wind through it. That was the very first thing we did when we moved here, was designate the pathways. From there we planned the succession not just from the middle of the wood to the outside but also from the woods, down to the paths. Right at the path edges we placed a lot of the really nice plants that we want to see all the time. Have fun with it! :o) Barb in southern Ontario, CANADA

The rebar and other reinforcements in the concrete expand and contract at different rates. That's not a problem with the usual minimal stable temperature ranges, but creates large enough cracks during a fire that it renders the foundation unsound for future bearing use. Not to mention the heat damaged plumbing contained within or under the slab also cannot be re-used. I'm sorry for your loss.

"why don't they simply dig a bigger hole and bring in a different kind of non-clay soil that doesn't need hydration?" When you dig a hole in clay soil, you end up with a hole that holds water. We use bentonite to build earthen dams. If you put other soil in that hole, all you get is a mud hole. Such a system works better in theory than reality. "We do that all the time for septic systems up here where you have bad soil." The drain field does not have a foundation to damage. The drain field is engineered to be able to handle a specific amount of water, and can handle the occasional 1" of water at a time during the rainy season without permanent damage. If you apply this strategy to the house foundation, you need to be able to pump out all the water that comes off the roof in a hurry, before it causes damage. This can easily be 600 gallons or more. Now, where do you put that water? You can not pump it over to the neighbor's lot, and a french drain will not drain fast enough in clay soils. You could add a 1500 gallon cistern and hope you never get that 100 year rain, and that that cistern doesn't crack like the foundation you are trying to protect. Such a system of putting other soils in a clay lined hole has a lot more maintenance than just watering the foundation. If the rain gutter downspouts do not go into a splash block that extends out into the yard 6', the water will find its way back to the hole you provided. You can't begin to imagine how many houses I have had to go back to to put the splash blocks back where they belong because the owner moved them because they were in the way of mowing the lawn. Or, where they add landscape edging that blocks the water from going out into the yard instead of back to the foundation. Now, if the pump that is supposed to drain the foundation doesn't work because nobody bothered to maintain it, you end up with a bigger disaster than if you never dug a hole for the water to go into in the first place. Clay soils wreak havoc on drain tile as the very fine particles eventually filter down and clog it. Read the link below, and you will see that the best practices are to build UP, leaving the natural drainage plane intact, instead of digging down into a hole, thus the reason for that much foundation showing. http://www.foundationperformance.org/projects/fpa-sc-01-0.pdf

The month is important becasue of the difficulty of excavating frozen ground and protecting the ground before and after the pour. It can be done with a lot of straw bales (not hay) or various heating methods. Did it for an IBM building in Essex Jct., VT but it was so unusually cold the foundation contractor went bankrupt.