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Kingspan GreenGuard Q350 Fanfold Underlayment

One of the Most Durable Products Currently Available

Designed to be used as a “leveling board”, it adds insulation and moisture protection during installation of new vinyl siding over old siding.

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Economical fanfold underlayment XPS 0.2" thick with crease-fold hinges

GreenGuard Q250 Fanfold Underlayment

Economical fanfold underlayment XPS 0.2" thick with crease-fold hinges
Economical fanfold XPS 0.3" thick with reflective facer on one side
Economical fanfold XPS 0.2" thick with reflective facer on one side

GreenGuard FQ350 Fanfold Underlayment

Economical fanfold XPS 0.3" thick with reflective facer on one side

GreenGuard FQ250 Fanfold Underlayment

Economical fanfold XPS 0.2" thick with reflective facer on one side
Kingspan GreenGuard Q350 Fanfold Underlayment on a transparent background.

GreenGuard Q350 Fanfold Underlayment

When every penny counts, you can rely on the performance of one of our most economical fanfold siding underlayments. The 0.3" Q350 is made of extruded polystyrene foam (XPS). Designed to be used as a “leveling board”, with crease-fold hinges, it adds insulation and moisture protection during installation of new vinyl siding over old siding. It is configured in fanfolded bundles 4’ x 48’.

Product Highlights

  • Lightweight, durable...cuts clean and easy

  • Perforated to allow moisture vapor to escape

  • Provides a smooth, level nailing surface for new siding