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By Bob Mulloy (Reprinted by permission of the author)

So, you walk around to the rear of the home and there it is - the deck! Every home nowadays just has to have one, and if one is not present, that seems to be no problem for the homeowner. They just buzz down to the local "you-do-it-center", pick up a load of lumber, and bang it together. Bingo, a deck is born! Or, the less handy homeowner might hire Mr. Flybynight, the carpenter who can certainly build a quality deck for a song and a dance.

Does the latter scenario sound familiar? Now we come to the thrust of this article, for as you know, we home inspectors must evaluate the deck and prepare a final report for our clients which includes our observations regarding the deck, along with the rest of the home.

Where to start? Let’s approach a deck inspection methodology by asking ourselves several pertinent questions:

  • Do the footings appear to be adequate?
  • What holds the deck up?
  • Is the ledger joist anchored to the house and is it flashed?
  • Is the floor frame undersized, over-spanned or over spaced?
  • Do the joists have proper end bearing?
  • Does the deck have a means of lateral bracing?
  • Do the handrails & guardrails pass your scrutiny?
  • Are the stairs safe?
  • Is there wood / soil contact or signs of decay or potential for decay?
  • Are there visible UNSAFE nail pops or splinters in the deck?
  • Documenting access & life - safety issues

2007910163953_MalloyFooting1.jpgFOOTINGS - Do the footings appear adequate? I like to inspect the deck from the ground up. I start by examining the visible piers or footings at ground level. If I find patio blocks, cement blocks, or five-gallon buckets filled with cement, then I automatically think "red flag" and investigate a little more carefully by probing. Up here in New England, all footings must extend a minimum of four feet below the ground to prevent frost heave, but all to often I must document "shallow footings beneath deck, potential for frost heave movement." You might include a disclaimer at this point: "DISCLAIMER: The actual depth of the footings that support the deck is undetermined and can only be determined by excavation and measurement."

Finding any visible shortcuts causes my inspection antennae to go up. I start wondering just who built the deck, the owner or a contractor, and why were these errors allowed? Was a permit pulled? Shift the burden of proof from your shoulders to the client's by suggesting that your client do a little research at the local building department.

While our focus is under the deck, how many times have you seen a crater beneath the deck that will retain surface water & roof run-off that will soak into the ground and end up in the basement? How many times have you seen vegetation left under the deck? How many times have you seen a dryer vent terminate under the deck? How many times have you seen the deck built right over the septic tank or the basement entrance or the oil fill & vent pipes? There are many things to consider that can be easy to miss.

200791019523_MolloySupport2.jpgSUPPORT - What holds the deck up? Working upwards in inspection methodology, the next components encountered are the columns or support posts and beams. I like to sight down the line of support posts from several vantage points to see if the posts are out of plumb, missing, improperly spaced, or excessively notched. If the support posts are wood, out comes my probe again as decay is very prevalent with wood decks. Some of the deficiencies I see in the area of support posts are downright scary when you think that the deck may be asked to support the weight of numerous people during a cookout.

Next, I check the base of each post to see if it is buried within the concrete footing, whether the post falls properly upon the footing and how it is attached. When posts are buried within the concrete, decay is likely in the future even if the wood is pressure treated. More importantly, the concrete footings are likely to blow apart from frost heave because the wood shrinks allowing water to enter each post hole.

I like to observe a posts that fall squarely upon the footing and do not dangle half off in space using a skyhook for bearing. Better still are post brackets that provide a means of anchoring between the footing and the post while separating the two to prevent decay.

When the posts fall beneath a beam, I like to see a top plate that anchors the two components together, or at least a proper nailing schedule. The presence of extra posts, sticks and braces usually indicate original poor workmanship and attempts to stabilize the deck frame from movement.

20079101984_MalloySupport3.jpgWhen the support posts are also used to support a let-in rim joist, floor joists and railing posts, then a whole new series of defects may be present. Over-notching or improper notching seem to be frequent flier problems. Sometimes, notches are cut too deep and the remaining wood is drilled out for bolts, leaving posts that easily wobble when the guard railings are tested with lateral pressure. Imagine someone leaning on the guardrail and the post suddenly breaks in half where it is notched! Ouch!

Built-up beams frequently rest upon the deck posts. The beam may be situated at the outside edge of the deck or several feet back to create a cantilevered effect. The problems with the built-up beams seem to fall within categories of improper splicing and inadequate nailing. Quarter-point splicing is best and the splices should fall above a post. However, Mr. Do-it-yourselfer can stretch a 2 x to infinity and beyond with no regard for load bearing, bending or potential collapse.

2007910191754_MalloyLedger4.jpgLEDGER - Is the ledger joist anchored to the house and is it flashed? The ledger joist is usually the first piece of stock fastened to the house. But simply face nailing the ledger board in place is not enough to both anchor and support the deck. The ledger board must first be flashed or held off by cleats to prevent moisture damage to the underlying siding, and then it must be secured to the house frame with anchor bolts. Time and again, I find both the anchor bolts and the flashing missing on decks built by so called professionals and inspected and passed by local officials. It seems that every summer there is a news story about a raised deck that has collapsed causing multiple personal injuries - tragedies that could have been prevented. As a home inspector, safety concerns should be paramount in your mind, so look under the deck when possible and check for lag bolts as a means of secure attachment.

email, or via his website.[/b][/size]

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Bob has given the "deck seminar" at the NE chapter of ASHI. I think he gave it at the ASHI National Conference. If he gives it in your neighborhood, pay the fee and drive the miles. It is worth it!! He has great slides and very understandable dialog. He speaks HOUSE and he speaks to home inspectors.

Go Sox

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  • 1 month later...

Plastic decks are not usually a problem as wood decks are in relation to WDIs.


There are also many problems related to ALL plastic products. Natural gas is used to produce plastics. Prices too are sky high.

http://www.plasticlumberyard.com/plasti ... #Landscape

Here is a bit about stone pavers

http://www.hgtv.com/hgtv/rm_deck_patio_ ... 11,00.html

and flagstone patios

http://www.hgtv.com/hgtv/gl_design_pati ... 15,00.html

and brick patios

http://www.hgtv.com/hgtv/gl_design_pati ... 08,00.html

patio makeover

http://www.hgtv.com/hgtv/gl_design_pati ... 82,00.html

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  • 6 months later...

What about building composite decks yourself? I used MoistureShield with good results.

Composite decking really is better than traditional wood decks because they are low maintenance and environmentally friendly. MoistureShield decking offers the look of deep wood grain in a composite wood decking material.

MoistureShield® Decking by A.E.R.T offers premium composite wood decking, railing and fencing for your home or business that is 100% PVC free. MoistureShield® Decks are low maintenance and are made from environmentally friendly recycled wood fiber and polyethylene plastic. All MoistureShield® decking components includes a transferable Limited Lifetime Warranty. We also offer a free online custom deck design tool.


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"Composite decking really is better than traditional wood decks because they are low maintenance and environmentally friendly."

Trex and the other composites are good materials, and I have used it on my own deck and a couple of others I have built. But...the one big drawback I have found with my own west-facing Trex deck is that the stuff really soaks up and retains the heat on hot, sunny days. There are times when you really can't walk comfortably on it with bare feet. And I have the lightest color they make. If I had to do it again (which I won't), I would go for Ipe (ironwood) over Trex, even though that's a bit more work to install.

I don't know if the composites with hollow channels have the same problem(?), but I'd be reluctant to recommend the solid "Trex" type decking for an exposed south or west facing deck.

Sorry for the slight thread drift...good article.

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  • 10 months later...


Sure, if it's not rotten or infested with insects. You'd be better off with new treated wood though. If the wood you reuse isn't treated and the rest of the deck is then that wood is liable to rot out before anything else on the deck - in which case, you aren't going to want to use it for joists, beams or ledgers or other parts that can't be easily replaced.

OT - OF!!!


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