Question
we have a very large L shape raised redwood deck.  This wraps around the house, has a Maple tree right in the middle and an above ground pool on the short L side (a portion of that side is 1 step raised too).  We are redoing this deck and looking at more maintenance free options like building a retaining wall and brick pavers  but don't want to loose the tree.  Can brick pavers work since we would have to backfill/raise the underneath about 3 1/2 feet with rock/topsoil.  Any other ideas?  This deck measures about 50 x 30.  What am I looking at price wise?  trec vs pavers?  I'm not crazy about the trec decking as it gets too hot for the feet of our kids & dog, as well as eventual maintenance for the wood platform below---HELP...

Answer
Michelle:

Unfortunately, to answer your main question, you can not fill more than a few inches of soil on top of existing tree roots. 3.5' would almost definitely eventually kill the tree. Plus, in order to be effective it would have to be very well compacted which is bad for the tree. Also gravel will usually through the soil PH off.

Given the description it seems like if you want the tree you really need to keep the decking. There are more options other than trex, there are other types of composite and plastic decking (Eon, Fiberon, etc.) Prices vary drastically depending on brand and type of product and prices are also dependant on your location. I have not recently priced a composite deck but you can get a new pressure treated wood deck for around $15, sf. (including structure)Trex and other composites are usually at least 25% more.

Color has a lot to do with how hot the decking is. Select one of the lightest colors for cooler deck. There are some decking materials that are 100% plastic and all white or light gray. These do not get too hot.

One last thought is that you can build your deck in wood and then cover it in one of these new outdoor linoleum products which will preserve the wood.

Best of Luck
Sean J Murphy, LA,ISA, LEED AP
Please check out my blogs and articles on landscape topics like this on my websites.
http://www.seanjmurphy.com
http://amenityarchitects.com