Your roof doesn’t have to come off to fix rotting rafters – here’s the smart way to reinforce them. NRCA indicates that three out of four rafter damages are repaired without a complete roof tear-off, which saves up to $5,000 or more in comparison to a roof replacement. Unless the rotting rafters, which usually occur due to leakage or lack of sufficient ventilation, are addressed, it may undermine the stability of your house. This “how to replace rafters without removing roof” guide provides a step-by-step process to repair rafters from the inside, keeping costs and disruption low.
Safety First: Important Safety Precautions
As rafter repairs are a structural job, focus on safety:
- Temporary Supports: Put acrow props in or braces of 2×4 under the roof deck prior to cutting.
- Permits required: Many cities require engineering permission to make structural adjustments. Check local codes.
- DIY or Call a Pro: Damage to more than 30 percent of rafters or visible sagging in the roof should mean you employ a structural engineer.
Safety means that you can install rafters indoors without the danger of collapsing. Check out our Wood Siding Repair services here!
Tools & Materials Needed
Gather these essentials for a successful repair:
| Item | Purpose |
| Reciprocating saw | Cut damaged rafters |
| LVL/engineered lumber | Stronger than traditional wood |
| Construction adhesive | Bonds, new and old wood |
| Hurricane ties | Reinforces connections |
| Laser level | Ensures straight alignment |
Optional: Inspection camera to assess hidden damage. Trust our expert team for Roof Repair Services!
Step-by-Step Replacement Process
Follow this sistering rafters guide to repair rafters without removing the roof:
Step 1: Expose the Damaged Rafters
- Go to the attic and take away any interior drywalling or insulation to find the rafters.
- Pro Tip: Before cutting a roof rafter, ensure there is no sign of rotten wood such as discoloration or sponginess using inspection camera.
Step 2: Install Temporary Supports
- Place adjustable jack posts every 4 feet under the roof deck to support the load.
- Brace adjacent rafters with 2x4s to prevent movement during repairs.
Step 3: Sister the New Rafter
- Option A: Sistering (Partial Damage)
- Cut away rotted sections, leaving solid wood.
- Apply construction adhesive to the old rafter.
- Nail or screw a new LVL rafter alongside the old one, overlapping by at least 4 feet on each end.
- Option B: Full Replacement (Total Damage)
- Use a reciprocating saw to remove the compromised rafter section.
- Install a new piece of LVL rafter, fasten with galvanized steel scab plates at each end.
Step 4: Strengthen the Connections
- Get stability at the ends of the ridge and the wall plate by adding hurricane ties.
- Insert through-bolts (and not only nails) to hold loads at key points.
Step 5: Insulation Reinstallation and Drywall
- Use spray foam to seal gaps that can leak air.
- In order to recover the look of the attic, replace areas with insulation and drywall, for expert solutions, check out our Roofing Installation Services!
Cost Comparison
| Method | Cost per Rafter | Time |
| Sistering | $50–$150 | 2–4 hrs |
| Full Replacement | $200–$500 | 4–8 hrs |
| Roof Removal + Rebuild | $5,000–$15,000 | Weeks |
Sistering is the most cost-effective approach for minor damage.
Final Thoughts
How to Replace Rafters Without Removing Roof? Sistering rafters is 90% cheaper than a full roof replacement if caught early. In this sistering rafters guide, you will learn how to fix the rotting rafters in your house internally, while avoiding costing thousands, and not compromising the structure. But in case several rafters (more than three) depict rotten roof rafters, please schedule a visit by a structural engineer to evaluate the damage. Take early precautions and prevent rebuilding your house at a high expense. For further assistance, contact Onlyroofing!
