Ridge board question


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Old 11-16-20, 05:38 AM
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Ridge board question

Remodeling a kitchen and the previous person put R7 insulation in 2x6 vaulted ceiling and then drilled several holes through the ridge board in each rafter space. I guess there way of venting even though there is no ridge vent. My question is should I sister the ridge board with some 1xs where all the holes are drilled. Looks like 8 to 10 1/2 holes in each rafter. Never seen this before?
My plan is to install rafter vents and insulate with R19. There will be a new roof eventually and will put in ridge vent at that point.
 
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Old 11-16-20, 05:46 AM
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A ridge board is not really a structural component. Rafters butt into it from opposing sides and don't rely on it for strength. A ridge BEAM is different because it is load bearing. So I doubt the pointless holes matter. However there may be other issues we can't comment on sight unseen. At any rate, adding short pieces of 1x would do nothing other than stop the very limited air movement. Air doesn't really move through small holes like that in a meaningful way.

R19 will fill a 2x6 space and leave no room ventilation. Ventilation in an underinsulated ceiling is counterproductive anyway. Your likely better off with no ventilation at all.
 
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Old 11-16-20, 06:58 AM
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Ridge board question

Wouldnt the rafter vents help with the proper ventilation. They are the plastic ones that you staple to the roof deck that provide air flow from the eave to the the ridge. As I said eventually I will be putting in ridge vent on with new roof.
 
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Old 11-17-20, 01:51 AM
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Btw xsleeper thank you for your response. After thinking about what you said I think I understand. The r19 would be compressed to much even with the rafter baffles. So what if I used the high density r21 (5 1/2) along with the baffles. Essentially reducing it to r19 from what Ive read. I realize its useless without the ridge vent but I was hoping it would be ok until the spring to put that in. That is unless I get a nice day between now and then.
 
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Old 11-17-20, 06:17 AM
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The point is that compressing fiberglass insulation is counterproductive. See chart.

If you never had ventilation before and you have no mold or moisture problems, what makes you think you need it now? IMO more R value is more important than any perceived need for ventilation. Air movement is fine in the summer but it speeds heat loss in winter. And the ceiling is where you need the most r value. In zone 5, the dept of energy recommends R-49 - R60 in attics. If your joists were 2x12 it might be a different story.

The best thing for a 2x6 rafter space, if you want ventilation, is a 3/4" x 3/4" cleat against the rafter and roof deck, then 1" XPS foam (edges sealed with PL300 and any butt joints sealed with tape) then R-15 fiberglass.
 
 

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