New deck stairs- rim joist extension


  #1  
Old 11-23-15, 02:55 PM
Mama DIY's Avatar
Member
Thread Starter
Join Date: Jan 2010
Location: USA
Posts: 39
Upvotes: 0
Received 0 Upvotes on 0 Posts
New deck stairs- rim joist extension

I have designed a stringer that will require 6" of rim joist to be fully supported. My problem is that the current rim joist is 7 1/8" long ((2) 2"x8" pressure treated together, so the rim joist is 3" thick) and the stringer will be placed starting just beneath that. What is the safest way to extend the rim joist and support the stringers? The stairs will be 8' wide, the total deck width is about 21'. Connecting them as inside stringers is not an option. I can provide photos if needed.
 
  #2  
Old 11-23-15, 03:25 PM
czizzi's Avatar
Member
Join Date: Jul 2007
Location: USA
Posts: 6,541
Received 15 Upvotes on 13 Posts
Sorry, your post is a little vague, I understand you have a double 2x8 rim, but what are the dimensions of the stringer? How high is the deck off the ground? What rise and run are you using? and do you step down immediately from the main deck or does the first tread extend out from the deck at the main deck height before descending? Pictures and sketches of any kind would be great.
 
  #3  
Old 11-23-15, 03:25 PM
XSleeper's Avatar
Group Moderator
Join Date: Dec 2004
Posts: 27,204
Received 1,949 Upvotes on 1,749 Posts
Read this several times and it makes no sense. Maybe a picture would be a good idea.

If I understand you right, you probably will want to lag another treated 2x12 onto the existing ledger. Then at the stringer attachment points maybe put some vertical 2x4 blocking in the void under the ledger.
 
  #4  
Old 11-23-15, 05:36 PM
Mama DIY's Avatar
Member
Thread Starter
Join Date: Jan 2010
Location: USA
Posts: 39
Upvotes: 0
Received 0 Upvotes on 0 Posts
Name:  630x400xstair-section-profile.jpg.pagespeed.ic.BMuRhAEpAb.jpg
Views: 17912
Size:  22.3 KB
I attached a photo but the dimensions didn't transfer. It shows how my stringer will sit as the first step below the deck, as an outside mount, but it would be attached below the rim joist. My drawings are on grid paper and difficult to see, but if you don't follow this I'll do my best to darken the lines and scan it.
Rise 7 1/4", run 11 1/4" stringer length 40 1/8". Total rise 29" (surface of deck) Total run 33 3/4". Rim joist is the top rise so the stringer is placed at 8 1/4" from deck surface (1/8" below the rim joist's lower edge), the deck is the top step. Decking is 5/4" pressure treated, stair treads will be 5/4" Doug Fir stepping, risers will be 3/4" Doug Fir. If I attached a 2x12 it would be done so at the same level as the existing rim joist, in which case it would still not fully support the stringer. The stringer would sill be a couple of inches too long...
 

Last edited by Mama DIY; 11-23-15 at 05:45 PM. Reason: Dimensions on photo didn't transfer
 

Thread Tools
Search this Thread
 
Ask a Question
Question Title:
Description: