Placing an insulation block

Winter Prep 3: Insulating Sérénité

Placing an insulation block

IMPORTANT NOTICE: This blog post documents and discusses how I insulated an area of my boat, it does not constitute advice on the best way to insulate your boat. Before undertaking a project such as this you should consult a qualified professional.

One of the things I learned from last winter is that life aboard can be a drippy affair. When the temperatures drop outside and the warm, moist inside air comes into contact with the cold hull condensation will form. This was particularly a nuisance for me in the closed spaces like the lockers and where things touch the hull like cushions, mattresses and bedding. My solution was to insulate the hull and below I describe how I did this to a portion of my boat and eliminated the condensation problem in that area.


  • 2.5 cm (~1″) R-5 closed cell foam insulation rated for ground contact and moisture.
    For this project I chose Owens-Corning Foamular™ 150. Read more about Foamular™ 150
  • Reflectix™ double reflective radiant barrier. Read more about Reflectix
  • Builder paper (for templates)
  • LocTite™ Power-Grab, heavy-duty outdoor rated construction adhesive. Read more about LocTite™ Power Grab adhesive
    *** A note about the adhesive: Ideally an adhesive that will quickly harden when used between non-porous materials would have been best, in my case I settled for a water-based, low VOC adhesive because of 1) concerns about adequate ventilation the space in which I was working, and 2) I live aboard my boat and didn’t want to risk breathing harmful fumes as the adhesive set. The downside of this decision is that it could take a long time (probably months) for the adhesive to fully harden.


  • T-square
  • Sharpie
  • box cutter knife with a long blade
  • scissors
  • caulking gun
  • masking tape

placing a foam block
Placing a foam block

Location: Onboard Sérénité, Back Creek, Annapolis, Maryland, United States, North America

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