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Deck Woes

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Jul 28, 2013, 12:42 PM
Deck Woes
Hubby is installing a deck. All was well, 1/8" drop per inch for runoff. With the deck being an 8' run. Should be a total of 1" run at the end of the grade.Well now we've noticed that the tops of the joist are about 1/2"from the ledger. After remeasuring: the grade is now at almost 2". We think there was some settling. What to do. Help is needed asap!And should the decking be applied to being flush against the house (basically partly on the ledger board)?
Jul 28, 2013, 01:30 PM
To begin with the ledger should not be attached to the rim joist of the house solidly. Meaning there should be a gap to allow water to run through. Same goes for the deck boards placed tightly against the house. You can block out with plastic blocking to allow an air space between the rim joist and ledger. If water is allowed to penetrate between the two it will most likely rot the rim joist. To help prevent this the area should be flashed between the ledger and rim. But using standard aluminum flashing with pressure treated lumber will corrode the flashing by a chemical reaction. You can use aluminum but then follow-up by placing a piece of 30# felt or ice guard between it and the ledger. In addition the house should be flashed to direct water away from the structure starting above the deck surface and continuing well past the bottom of the ledger/joist.

When you indicate that the joist are 1/2" from the ledger top. Is this elevated or recessed? There is no hard rule for the pitch. The 1/8-ft is the least. On my decks I often go more to make sure that there is good run off. Problem with a elevation difference (between ledger /joist) is the attachment of the deck boards. Different fixes for different problems.

This message has been edited. Last edited by: redoverfarm,
Jul 28, 2013, 01:49 PM
Ok, flashing was applied properly. The ledger is applied to the rim joists. The reason for the flashing is to not allow water to seep in behind the siding and ledger. Didn't know about a reaction between the aluminum and pt. PT is usually osmocoated or treated with formeldehyde. The joists are hung with joist hangers against the ledger, but for some reason (we think due to settling),the pitch went from one inch to one and three quarters inches. There for there is a a 1/2 inch gap between the top of the joist and the ledger board. At the bottom of the joist, it's flush with the ledger board. I guess it appears we are redoing the beams and reattaching the joists so they are properly set with the ledger. From everything I've seen (Dean & Derek et al.) the decking should butt up to the house. Gaps between decking should be an 1/8 of an inch on dry wood decking measured using a 16d nail. We're using cedar decking. Thanks for your response!
Jul 28, 2013, 04:57 PM
With the new CCA treated lumber you must use galvanized flashing and galvanized or stainless fasteners for the reason Red mentions. The CCA lumber has copper in it and copper and aluminum don't play well together.

General Disclaimer

Any advice given here is general in nature and is not necessarily valid for your given area. If in doubt check with your local codes enforcement department for what is required when doing electrical, plumbing or structural work on your house. Permits may or may not be required in your area and home owners may not be able to DIY some tasks. I have no way of knowing if you have the skills needed to complete the tasks you are asking about, when in doubt seek professional assistance.

My advice may be worth exactly what you pay me for it. :-) For the record I did not stay in a Holiday Inn Express last night.
Jul 29, 2013, 01:36 AM
I've got to admit, building a deck with a deliberate pitch is a first for me. Been building decks for decades and have made hundreds of them. All are set level. It's a deck - water is going to run off between the planks. If you are using PT material then you are going to have enough movement just in your decking material to make a 1/8" per foot pitch moot. Sorry to go against the flow here but there is no reason to pitch the deck.

Not going to disagree with all the other advice about attaching to the house and flashing. Best to make the deck a separate structure that only touches the house in a few points for bracing and stability. Since that's not always possible, you use spacers to keep the deck ledger away from the house. PVC washers around the bolts attaching the ledger to the house work well. If you do that there is no need for flashing.

If you do need to add flashing, 45 mil rubber roofing material works very well and will not react with the PT chemicals.

Jul 29, 2013, 06:25 PM
Thanks! Actually there is a coating on the flashing. All is well. Checked all out with my favourite pros, Dean and Derek from Indoors Out. They really helped out too. Thanks for your input. It's much appreciated!
Jul 30, 2013, 04:27 PM
I too never saw a deck that was pitched, say like a concrete pour leading water away from the house. No real need for it. One wonders who thought that was a grand idea. Too much thinking can hinder ones ability to perform the task at hand.

This message has been edited. Last edited by: CommonwealthSparky,

Popeye only reached for the Spinach can as a last resort...
Jul 30, 2013, 05:03 PM
Well if you live in the woods or close by you will notice that the gaps between the deck boards often disappear being filled in with debri from trees (leaves, pine neddles,pollen and the like). Now you have a good rainy season and the deck boards tend to swell. What was once a gap is no longer one. It does tend to lead water immediately away from the foundation/house wall faster. Even a slight pitch is not noticable in appearence and takes very little extra effort to accomplish it. I side with the old saying " Better safe than sorry".
Jul 30, 2013, 07:49 PM
The thing is, there is no reason to pitch a deck. It's a deck, it's not a waterproof surface. Even if it's perfectly level and even if all the joints swell and clog with debris if it gets rained on the water will follow a path off the sides. It doesn't make any difference if water cascades evenly through the gaps or if it flows outwards off the edge - the water is going to run off.

A pitched deck will feel 'off". I'm sure that I'm more aware of it than most but I can feel like I'm walking on an angle on a 1/8" or 1/4" per foot surface. In some cases, you may have a deck into a corner of a house. The deck will have to be pitched in at least one direction, making for an angled look and/or an uneven step-up for access. Furthermore, if the concern is debris clogging up the gaps a shallow 1/8" per foot pitch will do nothing to help drainage - you'd need a lot more pitch.

Sorry, but I just have to stick with my original assessment, there is no reason to make a deck out of level.

Jul 30, 2013, 09:20 PM
Well all of mine were pitched and are very comfortable to walk across. I doubt that anyone would ever be able to tell that there is a pitch. Any stairs or step up are made at the end of the pitched area so they are like any other stairs being level and correct rise and tread. I have actually watched during a storm or rain and the water does run the lengthwise of the deckboard. Most deck boards will sort of cup after time and not allow the run off to the edges. Eventually they will find a flat spot and change direction and run off into the gaps. Just that few feet means a world of difference to me limiting that drainage down into the footing and foundation.
Jul 30, 2013, 10:34 PM
It looks like we will have to agree to disagree on this one. No disrespect to your methods that you use at all, I just have a different opinion.

Oct 01, 2013, 09:39 AM
Originally posted by natineah:
Good ideas...However you deck your halls, though, make sure you fill it up with love, good company, and a joyous atmosphere. That beats the angel or star on top of the tree any day.

And this relates to the subject in what way??? Confused

Looks like another say nothing troll, or perhaps someone with a neurological disorder that prevents comprehension.

Natineah perhaps needs to be getting appropriate medical treatment.

This message has been edited. Last edited by: GardenSprite,
Oct 01, 2013, 10:12 AM
Random brain neurons firing?
Maybe too much joyous holiday celebrating...really early, and with Jim Beam?
Oct 01, 2013, 12:01 PM
I don't have an issue with happy, harmony, and unicorns for all... unless the unicorns are carrying banners over their backs for happy hour at The Whoopie House.

any durable insulating material separating the CCA treated lumber from other metals should work... when the stuff first displaced copper/arsenic PT wood, the This Old House guys overdrilled the deck support holes and put plastic tubing in them to keep the galvanized bolts from rotting through. thick hot-dipped galvanizing is generally considered resistant. when the lags/bolts have been sitting a while on the shelf, they oxidize, and another common name for this is "white galvanized."

if you're really worried about water backflow to the house, place the deck boards with the openings running perpendicular to the house.

and sweep it periodically so the leaves and maple seeds don't pond water.

when we replaced our patio door, I didn't like how close the sill was to the deck. so I shot three tubes of silicone under the sill. spread it at an angle away from the sill so there's no excuse for water infiltration. will have to use the oscillating tool to lift that when we redeck, but that's what a tool chest is for.

This message has been edited. Last edited by: swschrad,

sig: if this is a new economy, how come they still want my old-fashioned money?
Oct 01, 2013, 08:27 PM
Originally posted by Conrad:
Random brain neurons firing?
Maybe too much joyous holiday celebrating...really early, and with Jim Beam?

Conrad, I think you've solved the issue. Some folks just like to get a head start on the holidays - He/she should be pretty pickled by the time Christmas actually arrives. Let's hope someone else decorates the tree. And I think the Jim Beam or its alternate will provide this poster with plenty of false joy and atmosphere.
Oct 04, 2013, 06:12 PM
Want to thank all who responded. I ended up contacting Dean and Derek who were awesome btw. The deck is up,railings are being worked on and all is well.Pics to come!