The National Trust for Historic Preservation has created the following window preservation toolkits and information on understanding window design and construction, repairing, and guidance when repairing/replacing.
- Toolkit No. 1 - Repair or Replace Old Windows (6 MB, PDF)
- Toolkit No. 2 - Window Types, A Residential Field Guide (5 MB, PDF)
- Toolkit No. 3 - 10 Reasons to Repair Your Old Windows (350 KB, PDF)