Therma-Tru Doors

Door System Maintenance

All Therma-Tru door systems and associated components should be inspected and checked at least once a year for the following conditions: fading of door finishes, weatherstrip seal inadequacies, door bottom gasket or sill gasket wear, and vinyl threshold or oak riser splitting or cracking. Upon inspection if any of these components fail to function, they should be repaired or replaced as follows. 

Door Finishes

Clearcoats and Stains

All exterior finishes are affected by exposure and weathering from the sun, moisture and air pollutants. A simple application of a maintenance coat of topcoat will renew the protection over the stained surface on Classic-Craft and Fiber-Classic door slabs. Before top coat fails, reapply a fresh coat. First, clean it with a house hold detergent and water. Rinse and let dry. Reapply the topcoat approximately every 3-5 years or when the gloss starts to fade.

Paint on Classic-Craft or Fiber-Classic Doors

For fading, cracking, splitting, etc., of painted Classic-Craft or Fiber-Classic doors, stripping and refinishing may be required.

Paint on Smooth-Star or Steel Doors

For cracking, splitting or deteriorating paint finishes on steel doors, lightly sand surface of door and touch up to match overall finish.

Note for Outswing Door Systems

Swing-out doors must have all the edges -sides, top and bottom - finished. Inspect and maintain these edges regularly as all other surfaces. 


If the weatherstripping fail to perform (i.e, not sealing the door system properly, cracking, tearing, etc.) the weatherstrip needs to be replaced. remove the existing weatherstripping and replace.

Door Bottom and Sill Gaskets

If the door bottom gasket fails to perform (i.e., splitting, cracking, pulling away from door slab, etc.) the door bottom needs to be replaced with a new door bottom.

If the sill gaskets on outswing sills fail to perform (i.e., splitting, cracking, etc.) the sill gasket needs to be replaced. Pull the existing gasket and replace the gasketing for proper functioning of the sill.

Risers for Adjustable Sills

If the riser for an adjustable sill fails to perform (i.e., splitting, cracking, etc.), the riser needs to be replaced. Remove the existing riser and replace.

Vinyl Thresholds

If the vinyl threshold fails to perform (i.e., splitting, cracking, etc.), the vinyl threshold needs to be replaced. Remove the existing threshold and replace.

Corner Seal Pads

If corner seal pads are torn or missing, replace them.

Sealing/Resealing Areas

If a caulk seal fails to perform (i.e. waterleakage), remove existing seal and reseal area.

Stripping to Refinish


Choose a standard paint stripper. Paint or stain and topcoat can be removed with most methylene chloride based strippers. Follow the paint stripper manufacturer's directions and cautions for correct use. Check with the product manufacturer of your fiberglass door/stainable polyurethane product for details.


Apply the stripper, working on the small areas at a time

Tip:For a fiberglass door, apply the stripper to the (A) glass frame first and (B) the raised panels second, before moving on to the rest of the door

Remove the stripper within 2-3 minutes. If your fiberglass door/stainable polyurethane product has a facory-applied primer, it might be removed ith long exposure to paint strippers.

Tip:Use a nylong bristle brush for easier removal of paint and stain from the wood-grain texture. For fiberglass doors, grade 000 steel wood can also be used.

Wash off the reaming stripper. After the stain or paint has been removed, clean with mild soap and water to completely remove any stripper residue. Rinse well and wipe dry. Make sure the product is completely clean and dry before refinishing.