Low deck over patio slab


Old 06-07-04, 11:01 PM
Visiting Guest
Posts: n/a
Low deck over patio slab

I'm planning a 14-15' deep x 24' wide x 14" high deck that will cover a 10' deep x 12' wide patio. Trying to decide whether it's worth it to cut (one hole) out of the slab for a footing/pier or span the distance. Due to low clearance, beams will be in same plane as joists and rest on concrete piers.
Is the added support of B worth the effort of concrete removal? Thoughts?

A) 2x10x14-15' joists; (2) 2x10 beam at rim + ledger on house; 5 footings/piers
B) 2x8x7' joists; (2) 2x8 beams at midpoint and rim + ledger on house; 8 footings/piers

Bonus question: What is the consensus on mounting the ledger to plywood siding with spacers instead of cutting it out and flashing?
Old 06-07-04, 11:20 PM
Join Date: Mar 2000
Location: Arlington, WA
Posts: 9,238
Received 0 Votes on 0 Posts
Don't span across the slab. The distance is too far. If you have to cut a square of concrete out of the slab to get a pier block set, then do that.

The decks I build are almost always done with 2X6 joists, supported on 4X6 beams. I use a simple 5 X 5 pattern -- the joists span 5 feet between the beams, and the beams span 5 feet between the 4X4 posts. Increasing the size of either the joists or the beams so that the span can be increased usually isn't cost effective, and the decks that I have seen with longer spans (even though the beams and joists may be larger), always seem to be 'bouncier'.

Bonus question -- I avoid ledgers every chance I get!! Any hole you put in the siding is a place for water to get into the foundation framing of the house -- the rim joist, the mud sill, the subfloor, wherever. Freestanding!! My first beam is within 2' of the house, and I work out from there.

Thread Tools
Search this Thread
Ask a Question
Question Title: