a few questions about deck construction

I've looked and looked on DIY and other sites and I can't seem to find some simple deck construction answers. If you can assist please jump in! I'm building a 1500 sq ft deck with composite. If you know of websites with these specific drawings I'd be very greatful.
(1) My deck will have many levels. Most of the joists are 2x8, and it seems most sites recommend a 7" rise. How are the joists best constructed in that case? I'm thinking of overlapping the joists by 8", then attaching 2 vertical 8x16 pieces to the outside with carriage bolts. Then supporting the riser section with a 4x8 beam.
That's my own idea- like I said, I can't find drawings for a 2-level joist design anywhere. If you have a website or advise please feel free.
Like this: (o = carriage bolt)
------------------- upper | o|<----vertical boards on each side joist | o | ------------------- ------------------------------ | o | | o| lower joist ------------------------------------- ||| |||beam ||| ----- pier
Problem is- for say 20 joists, this is a LOT of construction, and a lot of materials. Particularly if there are like 4 rises in one deck section!
(2) I was planning to use piers to support the 4x4's. How deep should these go? How wide? Round or square? Should the post be best attached with those single-bolt standoffs, or with those stand-offs mounted into wet concrete? We live in Florida. The deck will be about 28" above the elevation.
(3) Can I use composite for rounded edges? I thought on some levels I may try to round them.
(4) Is the flashing on the house supposed to go just over the joists, or over the composite decking? I thought I might use like 10 inch flashing over the joists by the house to keep rain away from the foundation/ Would that work, or would it be bad for the joists?
(5) One site said to slope the deck away from the house, about 1" for every 10'. Is this OK to slope it in both X and Y that way?
(6) What special considertations are there for decking around a large, live tree?
Thanks!
BX1
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
I am sorry, I could not follow what you were trying to describe. You do know that 2x8s are 7 1/2" or less? They would work quite well resting on each other. If you really need a smaller rise or have larger changes of grade you can make multiple steps of 3 3/4.
(top posted for your convenience) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Keep the whole world singing . . . . DanG (remove the sevens) snipped-for-privacy@7cox.net

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Since you don't show a layout of the deck, one can only answer in generalities. Many levels & only 20 joists seem difficult to match.
(1) Place a beam along the changes in deck elevation. Frame the joists into the beam using joist hangers or ledgers. As an example not intended to be a structural solution place two 2x12 on edge at the change in elevation. As it suits the arrangements, the top of the beam can be set at the top of the upper or lower joist. If the upper joist sits on the beam, a band board can be used to tie the joist ends together and serve as finish.
(2) The masonry piers should be supported by and tied into continuous footers. If you are near the water, you need to set the footers deep enough to avoid undermining. If not, you need to set the footers on undisturbed soil. (3) Yo no intiendo jefe.
(4) Flashing must lap under the building paper or house wrap at its upper edge. It should lap no less than 3 inches at a point 6 to 8 inches above the deck surface. It should then cover the ledger on which the joists sit. A better approach for a low deck is to make the deck independent of the house. Thus a 1/4 or 1/2 inch gap allows the house wall as is.
(5) If the deck boards are set tight like a porch floor, sloping the deck is helpful - mostly to insure that what is supposed to be dead level doesn't happen to slope back against the house.
(5A) Setting the deck a half inch below any door threshold is critical. This keeps wind blown rain partially away from the door threshold assembly.
(5B) There really ought to be pan flashing below the threshold to keep water out of the house floor and floor frame.
(6) Give the tree room to grow. Set piers and footings to cut as few roots as possible.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Thank-You for this detail and to everyone.
I wonder- do you have a www site with a diagram of how the beam and hangers are arranged at the change in elevation? Does the upper elevation sit ON the beam and the lower HANG on the side of the beam?
THanks BX1
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
-- >

I would overlap the top & beam to sit flush & place a few splice plates across the gap
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Choose your deck elevations and attach the joists either way. longshot says place one set of joists on top of the beam. That's o.k. if you have enough clearance to the ground and if the step height is o.k. I could send you dwgs after I get back into town. in about a week. TB
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Since you don't show a layout of the deck, one can only answer in generalities. Many levels & only 20 joists seem difficult to match.
(1) Place a beam along the changes in deck elevation. Frame the joists into the beam using joist hangers or ledgers. As an example not intended to be a structural solution place two 2x12 on edge at the change in elevation. As it suits the arrangements, the top of the beam can be set at the top of the upper or lower joist. If the upper joist sits on the beam, a band board can be used to tie the joist ends together and serve as finish.
(2) The masonry piers should be supported by and tied into continuous footers. If you are near the water, you need to set the footers deep enough to avoid undermining. If not, you need to set the footers on undisturbed soil. (3) Yo no intiendo jefe.
(4) Flashing must lap under the building paper or house wrap at its upper edge. It should lap no less than 3 inches at a point 6 to 8 inches above the deck surface. It should then cover the ledger on which the joists sit. A better approach for a low deck is to make the deck independent of the house. Thus a 1/4 or 1/2 inch gap allows the house wall as is.
(5) If the deck boards are set tight like a porch floor, sloping the deck is helpful - mostly to insure that what is supposed to be dead level doesn't happen to slope back against the house.
(5A) Setting the deck a half inch below any door threshold is critical. This keeps wind blown rain partially away from the door threshold assembly.
(5B) There really ought to be pan flashing below the threshold to keep water out of the house floor and floor frame.
(6) Give the tree room to grow. Set piers and footings to cut as few roots as possible.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Since you don't show a layout of the deck, one can only answer in generalities. Many levels & only 20 joists seem difficult to match.
(1) Place a beam along the changes in deck elevation. Frame the joists into the beam using joist hangers or ledgers. As an example not intended to be a structural solution place two 2x12 on edge at the change in elevation. As it suits the arrangements, the top of the beam can be set at the top of the upper or lower joist. If the upper joist sits on the beam, a band board can be used to tie the joist ends together and serve as finish.
(2) The masonry piers should be supported by and tied into continuous footers. If you are near the water, you need to set the footers deep enough to avoid undermining. If not, you need to set the footers on undisturbed soil. (3) Yo no intiendo jefe.
(4) Flashing must lap under the building paper or house wrap at its upper edge. It should lap no less than 3 inches at a point 6 to 8 inches above the deck surface. It should then cover the ledger on which the joists sit. A better approach for a low deck is to make the deck independent of the house. Thus a 1/4 or 1/2 inch gap allows the house wall as is.
(5) If the deck boards are set tight like a porch floor, sloping the deck is helpful - mostly to insure that what is supposed to be dead level doesn't happen to slope back against the house.
(5A) Setting the deck a half inch below any door threshold is critical. This keeps wind blown rain partially away from the door threshold assembly.
(5B) There really ought to be pan flashing below the threshold to keep water out of the house floor and floor frame.
(6) Give the tree room to grow. Set piers and footings to cut as few roots as possible.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
www.lowes.com select "design a deck" after you answer all the questions, it will give you a 3-D drawing with several views of a finished design

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.