Overlapping 50yr old decking with ply?
BilljustBill
| Posted in Construction Techniques on
The 1/2″ cdx decking is laid over 50 yr. old 1×6 tongue and groove. Ringshank nailed to the the rafters and old decking. Old decking is not rotted or in bad shape, but has had 6-8 roof replacements in its day.
Is $110 a square a good price for a 45 sq., 3/12, gable/hip roof? How much more do you think Advantec sheathing would cost?
When the new decking is installed should I expect to see those metal edge clips in this type of overlay procedure?
Thanks, Bill
Edited 8/20/2008 9:56 pm ET by BilljustBill
Replies
What's the rafter spacing? If it's 16oc you won't need the H-clips (metal edge clips) even on new construction.
Don't have an opinion on the other stuff, yet as long as it's nailed well into the rafters and not the old board decking. Need to use 12d or 3" ringshanks due to the increase of the old deck.
I am a bit confused. Are you planning on laying 1/2" cdx over this or is this the existing?
Frammer,
I'm overlaying the 1/2" cdx on the old existing 1x6 tongue and groove decking that 50 years old. It's not rotted or badly broken-out, but it has had all those past roofs and here and there are a 6-10" piece broken out or split around a knot. Also I can see a 1/4"-1/2" the 30# felt in between some gaps of the old t & groove.
I'm just concerned that if it is showing its age, and I have the means to put on the new overlay now while the shingles are being replaced, it can be done. In the future, I'm not sure the insurance companies will replace the next roof, fully, the next time we get 30 minutes of golf ball size hail or worse.
I'd like to hear your thoughts and experience.
Bill
Been doing it for years. Shingle manufacturer won't honor warranty over old boards.
Not that they will anyway.
Still makes a better job. Much better!The best reward for a job well done is the opportunity to do another.
"Not that they will anyway."Ain't that the truth!
Finally! We share the same opinion on something <G>.The best reward for a job well done is the opportunity to do another.
I just did that on my house last year. I used 7/16 OSB as strenth is in the t&g boards underneath. I felt there was no reason not to use the less expensive material.
Your price is in the ball park for around here.
Frammer,
Thanks for sharing your experience. Did you go back with 15# felt or 30#? Down here in North Texas, using 30# instead of 15# adds about $250-300 to the job.
I going back with a heavier shingle, GAF/ELK Armor Shield II. It will pay for the difference in 5 years with a $380 drop in my homeowner's yearly preminum.
Thanks again for your help,
Bill
15 if it is covered right away, 30 if it has to stay any lenght of time uncovered.
If it's new decking try the new synthetics for underlayment
Around here, Advantec is priced comparably to CDX, possibly even a little less. The H-clips aren't necessary but they help keep the plywood spaced.
Have overlaid a lot of old barn and house roofs this way. Nothing wrong with the method as long as the rafters are sound.
yup, all sounds real good.....heard of some characters though, made the assuption that the t&g roofboards were not a finished ceiling on a high end 3 season camp....nails galore,not sure how they fixed that one...get out the grinders?