I am building a deck attached to the back of my house. I’ve heard that it is a good idea to slope the deck slightly so that rain drains away from the house. I did that, only the slope seems a bit too steep- a drop of 1 3/4″ over 12-feet. The construction of the deck is very basic- with a ledger attached to the house and a 4×12 beam located 12-feet away and parallel to the house. My questions are:
Will the current slope be noticiable?
What level drop is recommended?
Since my deck boards will be parallel to the house and gapped 1/8″, is there anything wrong with making the deck perfectly level?
To level the deck, I am thinking of tacking a pressure treated 2×4 to the top of the beam which would make the deck almost perfectly level. Is this an acceptable technique?
Thanks,
Lyptus
Replies
Will the current slope be noticiable? If the wife comments, then it's too much.
What level drop is recommended? For a deck, as you noted below, it can be flat. Otherwise 1/8" per foot would be the most I would go.
Since my deck boards will be parallel to the house and gapped 1/8", is there anything wrong with making the deck perfectly level? Works well.
To level the deck, I am thinking of tacking a pressure treated 2x4 to the top of the beam which would make the deck almost perfectly level. Is this an acceptable technique? Yes, as long as it's tacked well enough so it does not slip out of position. And don't forget the the floor joists will need to be fastened to the giant shim.
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That is a little bit much, just aq wee bit.
I aim for 1/8" / footso that works out to 1-1/2" in twelve feet.
But I run decking perp to the house most times. With it running parrallell, the pitch won't do you any much good.
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So if I level the deck, is it logical to just add a 2x4 to the top of the beam?... or is this a bad idea, structurally?- Lyptus
I can't see all the details of your construction, but it basicly sounds fine to me. I don't know how much you already have done and how hard it would be to insertt that 2x4, or if it would be easier to shim at the bottom of the posts. I use a Simpson post mountand might prefer to shim under it. so deciding where to shim it up depends on all the details of what has been done and how it was done, which I am blind to from here.
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If you shim at the simpson base plate, does that create a problem mofing the fasteners an inch and a half closer to the end of the post? Any problem with splitting?
"When asked if you can do something, tell'em "Why certainly I can", then get busy and find a way to do it." T. Roosevelt
I'd shim UNDER the base plate, grout, and use a longer bolt. probably do it by jacking up slightly higher than needed and letting it back down after things set up.but this is all contingent - I don't have a view of what is existant now. Maybe he has posts set into crete four feeet down under...
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My 4"x12" beam is secured to four notched 6x6 posts with carriage bolts and the posts are nailed into post achors which are secured to concrete footers. It is not possible to shim under the posts without replacing the posts completely. This could be done but would require recutting, re-notching, and re-leveling the new posts which would entail a lot of work. The easiest solution for me would be to just nail a 2x4 along the top edge of the beam and then rest the joists on top of the 2x4. My fear though is that in doing so I'll violate some structural engineering principle and that the 2x4 would compress or otherwise compromise the structural integrity of the deck. So should I go with adding a pressure treated 2x4 or do I really need to recut new posts? Also- is nailing the 2x4 to the beam adequate or do I need to use some sort of adhesive in addition to nails?Thanks again,
Lyptus
gravity will hold it in place. No need for anything extraordinary. Nailing a 2x4 on top will work just fine.
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I always use pressure treated plywood for compressed shims....I usually save the odds and ends of PT plywood just for that purpose....much better than using dimension lumber, although for a deck, I guess it doesn't really matter a whole lot.
If you mentioned what kind of deck planks you're using, I missed it.
If you're using one of the composites, like Trex, the planks are crowned (when installed correctly) and a slope is not really needed.
As others have stated, however, I always slope my deck framing about 1/8th per foot in the event someone down the road decides to install a roof deck or something.
I would think the gap between the boards would be sufficient for drainage, especially if the boards are 4" wide and properly sealed.
That's a wee bit much. It'll function just fine, but it may be noticeable to the eye which is something you really don't want.
Here's what we often do for decks with the decking running parallel to the house. We install our ledger and then set the joists just about 1/8" or so down from the ledger. This gives that first deck board just a tiny bit of pitch to keep any water from collecting on it or worse, running back towards the house and siding. The joists are run level from there as the rest of the water will drain between deck boards.
Where you're at now, I'd just spike 2x ripped to the width of the top or your beam, to the beam itself. You'll still have an imperceptable amount of pitch but it won't stick out like an afro at a bald man's convention.