UnExCo Home
Pest Info Central
Wooden Sheds

Last Update: 11/11/15
Content copyright protected by Copyscape website plagiarism search

Wooden Decks
There are several routes to take.  First thing to decide is whether you use pressure-treated wood or not. The choice for non-pressure-treated boils down to plain wood, redwood or cedar.  "Plain" wood generally means two kinds, spruce or some kind of pine. Redwood, of course, comes from California, and cedar (usually eastern white) comes from New England.  Don't use plain wood.  You'll replace it in six to eight years.

Redwood and cedar are, however, resistant to moisture and insects, but not impervious. Their resistance is variable, depending on the grade, the age of the tree and the even whether the original tree had a western or eastern exposure.  Cedar is the choice if you want to stain or paint.  It takes both nicely, but can also remain completely unfinished.

People with deep pockets can take the secondary path by using redwood.  Remember, however, that redwood isn't meant to be structural.  Actually, it's more decorative than structural, and much too soft to use for things like stair treads.  And, after a few years in the weather, redwood loses it's distinctive coloring, and will look like any other wood. Before you specify redwood, check the price.  Even low-grade redwood (with lots of knots) will give you a quick case of sticker shock.

Naturally, we think you shouldn't use ANYTHING except the proper grade of pressure treated lumber.   Pressure-treated yellow pine is just about the all-around best, lasts the longest and is the most economical.  Even though pine is technically a softwood, yellow pine is hard!  This is what they use for stair treads - tough stuff.

Wood for pressure treatment is placed in a hermetically sealed vat, then all the air is evacuated, and replaced with the preservative.  The chemicals then penetrate deep into the wood.  You can't dip or paint wood and get even close to the same protection.

CONS:  Pressure treated wood is treated with arsenic and other toxic compounds and should not be used inside a structure;  it doesn't take staining well;  it has a tendency to "cup" or even warp;  and can split if not nailed or screwed properly.  For these reasons, it can present problems to contractors not used to working with it.

Let's start at the very bottom.  Put in a proper foundation.  Concrete pilings are the best, extended up to ground level, under each support.  No termite pre-treatment necessary. The builder comes in with a giant post hole digger, drills holes in the ground and fills the holes with concrete.  Build up from that, using aluminum heel plates between the concrete pilings and wooden supports.  These plates will keep the joist or girder ends above the earth and moisture.  You don't want to have ANY earth-to-wood contact.


While we're still at the bottom, let's consider something else. How much room is there going to be under the deck?
Your deck should be accessible to ALL animals or NO animals.  If you leave just an inch or two or three, expect visitors.  Meaning that little animals will find the area underneath just fine for them.  Sounds cute, maybe, but this is not good.

 You do not want little animals under there!

Close it off completely, or leave space enough for predatory animals to get in too.  That way you won't have any little animals making a home(s) under there.  A few years ago, we took care of a skunk that had made it's den under a deck with only an inch or two of clearance.  By the way, after rain, the owner said it smelled like skunk for two years. At which point, we tried a method that worked.

What's the best thing to put on the ground, under the deck, you ask?  Rocks.  The bigger the better.  Those large, rounded river rocks are the best.  (They should also be in your open window wells too.)  Rocks will not harbor small animals and insects like dirt will.  If you went by the book, you scrape the soil clean of vegetation, cover with (pierced) black plastic, or you can use plastic netting, then two inches of large-sized gravel, with a topmost layer of the river rock.  Actually, just the large river rocks should be good enough.  To animals and insects this is a virtual desert.

Be sure to consider how your rain-handling system will work and reroute any rain gutters and downspouts so that extra water drains away from the house.  This is especially important if your deck has no clearance underneath.  Decks with little or no clearance that develop drainage problems will have to be removed if corrections are necessary later on.

You should also consider termites when constructing your deck. Improper drainage contributes to termite invasions, and you might have to remove parts of your deck to remedy the problem. Have the areas you intend to construct your deck inspected and pre-treated, if necessary, to keep your home termite free.

Citronella Ants

Oftentimes, citronella ants, so-called because of their distinctive odor of citronella, will nest in structures, mostly under concrete slabs. These ants often "swarm," just like termites, in the spring and/or fall, always raise havoc because they are so often mistaken for termites. Citronella ants, however, are harmless.
citronella ants

New Jersey Citronella ant
When this swarming happens on the inside, regardless if they're termites or flying ants, you can vacuum them up for a non-toxic solution to the problem.  This problem can also be "historic," and happen each year. Consult with your exterminator about continuing swarming problems.

Swarming eastern subterranean termites look like this.

One thing you should always think about, when building your deck, are the bees.  More specifically, paper wasps and yellow jacket wasps.  Both of them have a habit of building their nests up "under things."  They like the rough surface, makes it easier to attach their nests in a protected area.

Solid benches are best
If you'll notice, the benches in the picture at the top of this page are made out of solid wood.  This means that there are minimum areas for wasps to build a nest.  As opposed to slats built on a box frame.

If your benches are already constructed with a box frame that allows wasps to build nests under them, staple common insect screening underneath the benches in such a way as to keep the wasps out. Naturally, you want to do this in the early spring before any nests are constructed.

Hornets, such as in the photo to the right are usually best handled by a professional.
bald faced hornet nest

Specify the use of screws.  Not nails.  Your builder will complain about that.  And to do it the right way means drilling pilot holes for all those screws, and it will be more expensive that way, but it sure makes for a tight, quality job!  Not only that, but if you have to replace anything it will be a lot easier with screws.  If the plumber, electrician or exterminator has to get under there, the screws will make it accessible.  Screwed-down decks also last longer.  We find that nailed-down decks are much harder to take apart without damaging wooden components.  Make sure that any fasteners you do use are galvanized, brass, aluminum or stainless steel.  Don't use brass at the shore.  And don't let your builder use a machine-inserted screw nail.  Any repair will be almost impossible. Screw nails NEVER come out.

Deck kits are definitely cheaper than custom built, but the downside is that they are generally inferior to custom installations.  Often they are manufactured with odd-sized or manufactured components that don't use standard lumber specifications.  If you can't find the manufacturer later, you might be faced with buying custom milled lumber.  Use or specify standard spec lumber.  You won't be happy with a kit-deck.  Trust us on this one.

If it's pressure-treated, save your money - it's not necessary. Pressure-treated wood will weather quite nicely without any of that stuff. And nowadays, paints have no lead and no mercury. Better for us, I guess, but now it offers no protection at all, just color. Consider these coatings only if want a certain color. If not, save the time, effort and money and let it weather naturally.

Myself, I like Wolman® preservatives and stains, and no, I don't have any interest in the company, nor have I ever accepted any fees from them! I just like their product. For a clear stain, get the Wolman Raincoat.

Just remember, however, if the wood is plain wood, then despite what you might see on TV, there is no preparation you can spray or paint on plain wood that will make it last appreciably longer. Don't get sucked in by Madison Avenue.

A bad idea. Unless they are moveable and you actually move them around. These items retain moisture, dirt, and other really bad things. If they are moveable you can take them out and hose them off. The moisture is what really makes things worse. Permanently laid rugs will hold moisture against the wood, and even pressure-treated wood will eventually succumb to this.

It's really up to you.  Just don't put any up against the house.  Planters should not be permanent, and should be able to be emptied, if necessary.  You might not always want them there.  Don't use soil from outside.  Buy sterilized potting soil, and don't import bugs. Construct and use planters as "holders" for plants that are properly potted and able to be moved.  Jacuzzis and whirlpools should have access for the trades - including us!

Construct and site your Jacuzzi with an eye towards controlling moisture problems, you'll invite carpenter ants almost for sure. Other ants too. Make it accessible for maintenance and moisture control.

Spend the money for a good skylight, but have it installed by a reputable builder.  A roof is always a good idea., but if you put a roof over your deck, and attach the roof to the house, be sure to have enough pitch to the roof to slough off snow and water so it doesn't wick back into the main structure.  We see a lot of carpenter ant and termite problems in slightly-pitched roofs that have been added to a house.  Specify all pressure-treated wood if it is open to the outdoors.  If you don't, the carpenter bees will find it in a couple of years.  That's another story.

Florida, or patio rooms are like skylights.  It is extremely important to get the right contractor using the right Florida room.  Each manufacturer is different from the other, so make sure you use a company that's been around awhile.  Most of the time these Florida rooms are made of aluminum, manufactured in kit form and installed by a local contractor.  If the local contractor doesn't do his job exactly right, you may end up, a few years later, replacing the whole thing.  To give you some idea of what can go wrong, you can look at an improperly constructed Florida Room.

Obviously, wherever you have failures or replacements, especially early in the life of your deck, you might want to replace with the pressure-treated type.  This means high wear or moisture contact areas.  Screw those items on, use brass screws in pre-drilled holes. When (not if) you do it again, it'll be easy.  Do the same when you replace any outside doorway kickplates.

Oh.   One last thing.  Always let your exterminator know that you are working on your deck.  Even though your deck may not be a termite hazard in itself, it may be positioned so that it affects the termite conditions of your house.  If you are under a termite contract with any exterminator, be sure to call him and tell him, even if you are only making changes or renovations to your present deck.         (See below...)

Wooden decks, attached to the house, can obstruct the proper treatment of a termite problem, necessitating removal or alteration. The type of construction determines as to whether this is going to be easy or difficult.  With the deck pictured, the deck boards have been removed to permit treatment of the old step that seems to be causing an ongoing termite problem.  The inside is a finished basement wall, so there is no real access from the inside.
Deck Opened for Termite Treatment....


Sheds should be considered the same as decks.  Don't buy one that isn't all pressure treated wood, inside and out.  It's probably best not to set it direct on the ground, without preparation.  Best, of course, would be to BOLT the shed to a standard four-inch concrete slab.  You cast the bolts right into the concrete, then bolt the shed to the concrete.  If you pour any slab at all, make sure it's at least three inches thick. Make the slab wider than the shed, form a curb and make sure the slab is pitched correctly to drain water.

If you don't mount the shed on a slab, and many people don't, mount it on pressure treated 6x6's.  Scrape the ground underneath your shed clean of any vegetation, cover the bare ground with pierced (at least 3 mil) black plastic, then those rocks I mentioned above. This helps keep those little animals from using the underneath parts of the shed as a condo.  As with your deck, allow NO animals under, or ALL animals under.  If your shed is bigger than, say, six feet or so, you'd want to mount it on a slab, properly, for stability and to eliminate any space underneath.  Larger than six feet, it approaches the specification of "permanent structure."

Most sheds are now factory made, and sold as kits to be put together by the homeowner or erected by a carpenter.  Most are also not ventilated properly.  An improperly vented shed will certainly give you problems down the road.  DO NOT insulate your shed unless the wife (or the hubby) tends to banish you out there.  Get the carpenter to install a couple of LARGE METAL soffit vents that will give the shed some cross ventilation. Put in MORE vents than you think you should, and put them on the bottom AND the top parts of the structure.  You want to have as much air change as possible.  Be sure to back it up on the inside with some hardware cloth, staple it right over the vent to keep out squirrels and other more determined animals and, finally, insect screening to keep out the wasps looking for a nice place to make a nest.  The vents are easy to install even if you're erecting your own shed.  You generally need no more than a drill, a jig or hole saw and the vent.  The vent can be purchased in any hardware store or wherever you purchased the shed.

Don't keep foodstuffs, trash, birdseed, or even grass seed in your shed.  All are considered "food" by these animals, and they'll be in it in no time.  And don't store upholstered furniture in an outside shed.  Mice just LOVE upholstered furniture.  You should see the little tunnels they make, all through your stored sofa.  Outdoor type cushions might be okay, it depends.  

A shed is where you might want to routinely use bait for the mice that will enter.  Put it on the floor, right next to the wall, write the date on the package, and inspect the package occasionally, to detect any activity.  See the Mouse Page.

You can also roll your own bait placements!  It's easy, cheaper, and, if you're good, much more precise.
Roll your own!

I don't use any bait in my shed, (I'm cheap) but when - and not if - I notice there have been mice inside, I'll leave the shed door open for a couple of nights and let the neighborhood cats clean up the problem.  Don't do this for too many nights in a row, you don't want anything deciding that this shed of yours is a good home.  You can do this a few times a year without worrying about homeless animals taking up residence.


Do you wonder about the safety considerations using pressure treated wood products? Check these sources for more information.

American Wood-Preservers' Association - This organization establishes the standards for the entire wood preservation industry.  A commercial site, granted, but the straight scoop.

Arch Wood Protection, Inc., of Smyrna, Georgia, is the largest producer of treated lumber, including the Wolmanized® brand. An excellent source of industry information.

What is pressure treated wood?  Another commercial site, but a good description, with some nice pics

Archadeck - Here is a good commercial deck builder - America's premier deck building company.

And if you have questions, we have a public Message Board where you can browse questions and answers on all subjects.

I keep this site in flux and under constant construction.  If you have any comments or
recommendations about my Web site, you can tell me about it
right here.

Browse visitor's suggestions here.