Removing a Wood Deck - Backyard Demolition
This is Part 5 of 9 in our Series on Restoring Wood Decks and Building New Wood Decks. Navigate to the first article: Restoring a Wood Deck
So far, we have looked at spot repairs, taking care of limited problems in your deck. But if you have extensive damage, with numerous rotting joists or bad beams, soft deck boards or rotting ledger boards, you may have no choice but to rip the whole thing out and rebuild.
One note: When pricing a project, people often forget to figure the cost of demolition--just disposing of the debris easily will cost $100 and very possibly much more. You are looking at several trips to the dump in a pickup, so it might be worth your while to rent a dumpster.
If you have ascertained that you only need to replace all the boards--that your support structure is sound--they can be ripped off with haste. Go after them with a pry bar, pulling nails out of the joists as you go to avoid injuring yourself on them. If the boards and nails are not popping off easily, cut the boards into smaller pieces with a power saw so you are prying against only a couple of nails at a time.
But if most of the boards are bad, it's likely your support structure has to go also.
Plan of Attack
It's time to haul out the chainsaw. Your plan of attack depends on the type of deck you have, keeping in mind you want to chop the deck up into convenient pieces that can be carried easily to your pickup or dumpster.
If your deck is at ground level, you can hack into it pretty much however you want. You just have to make sure you don't saw into dirt, which can dull the chain as fast as hitting metal. If however, the deck is elevated, you need to plan--you don't want chunks of deck falling on landscape, cars, bystanders or yourself.
Usually, you can get the deck to drop safely by sawing through the boards, parallel to the joist, and then sawing through the joists every five or six feet. You might need a sturdy stepladder to do this, though usually you can do it from atop the deck as long as you are careful when it's time to cut the beams. (Of course, the final cuts will have to be from a ladder.)
Cut Deck Debris to Fit
If you are using a pickup to haul debris, you can be clever and cut the sections about the size of the bed--maybe three joists wide. Make the first two or three sections narrower to accommodate the wheel wells. A section the size of your pickup bed is probably too large for one person to carry, but if you have a helper, it works well.
Another debris tip: With a sledge, slam the joists over flat against the boards before you stack the sections in the pickup or dumpster--they will fit more compactly.
Beam Me Down
It is best to cut the joists off the beam and then cut up the beam separately. Falling beams are dangerously heavy, so remove them a section at a time--when you have cut away joists past a supporting post, remove that section of beam. The rest of the beam will be anchored by the remaining deck, and the small section of beam you are removing will be a more manageable size.
The last element to remove is the ledger board, or whatever system was used to anchor the deck to the house. Nowadays, many jurisdictions require a ledger to be screwed to the house with 3-inch lags on 16-inch centers. If your ledger is lagged, haul out the ratchet wrench and unscrew them (a pneumatic impact wrench makes this task a breeze). It is likely your old ledger is attached with 16d nails, not lags; if so, haul out the cat's paw and dig in.
You should replace the old metal post holders--even though they are galvanized, they will deteriorate and maybe even rust through. If the post holders are set in concrete--not just pier blocks--you could be looking at a lot of muscle work to remove them.
Your deck is now demolished. Next let's look at options for deck materials.
Next article: Choosing a Decking Material. An overview of wood, composites and plastics for decking.
Jim Mallery, a semi-retired journalist and onetime registered contractor, has extensive experience remodeling, repairing, and rebuilding homes.