Remove Foam Insulation?


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Old 04-12-21, 08:34 AM
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Remove Foam Insulation?

Hi, New to this forum and hope you can help. I am gutting what was once our kitchen (built on piers) and converting to a screen porch. I have removed the flooring. Planning on covering the existing substructure with strips of Ice & Water Shield to protect from water damage, and replacing the flooring with 5/4" treated deck boards. My problem is that there is sprayed-in foam insulation under the present flooring, flush with the tops of the floor joists. I am concerned that, if left in place, it will cause a water/moisture trap and perhaps rot the existing substructure. I am thinking that removing the foam is the best answer. Any thoughts on this would be appreciated.
 
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Old 04-12-21, 05:36 PM
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Let's back up. You're concerned about water damage. Are your floor joists treated lumber?
 
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Old 04-13-21, 12:29 PM
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No they are not. The house is 100+ years old, some of the joists have evidence of rot and have been sistered with new lumber. Not really feasible to replace the substructure, that's why I thought I would cover them with ice & water shield to protect them from blown in rain. I live in south Louisiana and we get a lot of rain and moisture.
 
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Old 04-13-21, 01:18 PM
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There is a reason decks use PT lumber, you really can not build a deck with non treated lumber, it will not be protected from the elements!
 
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Old 04-13-21, 04:08 PM
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I've seen how things are done in S Louisiana so I understand. Yeah you would remove foam and completely wrap your joists with a product like Grace Vycor. It's not meant to be a permanent flashing, but I doubt you want to go to all the work of cladding them with aluminum trim coil, just to keep them dry, but that's one idea.
 
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Old 04-14-21, 09:15 AM
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Thanks Sleeper. Is the Grave Vycor the same type of material that TREX is now advertising for covering deck joists?
 
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Old 04-14-21, 11:04 AM
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No but it's similar. Vycor comes in wider rolls and would be more suitable for covering the sides of your joists, to protect them from weather. The Trex tape is only wide enough to do the tops of the joists.

Vycor Plus is offered in 4in., 6in., 9in., and 12in. widths.
 
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Old 04-19-21, 10:05 AM
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Thanks for your responses. After some more demolition it is evident that I will have to replace the joists/sills/plates after all, with treated lumber. The foam was wet like a sponge with all the rain that we have had and would have had to be removed.
 
 

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