IBHS research found soffit materials missing in approximately 75 percent of homes that suffered significant hurricane damage.
When soffit materials are blown off, the result is wind and water damage to the roof decking, attic and possibly the home’s interior.
Proper Fastening is Critical
While IBHS has found that plywood or wood soffits are generally adequately anchored to wood framing attached to the roof structure and/or the walls, it has been common practice for vinyl and aluminum soffit panels to be installed in tracks that are frequently very poorly connected to the walls and fascia at the edge of the roof overhang. When these poorly anchored soffits are blown off, water intrusion increases significantly.
To be properly installed, vinyl and aluminum soffit panels should be fastened to the building structure or to nailing strips placed at intervals specified by the manufacturer.
Inspect Soffit Connections
Nails and staples are not enough
Some soffits have wood supports but the soffit material is not adequately fastened to the wood. More often, no wood backing is installed and the vinyl or aluminum channels are stapled or nailed to the wall.
If soffits extend more than 18 in. from the wall:
Push up in the middle to see if there is a wood support.
If you have an older house, it is possible that the vinyl or aluminum soffit was installed over an existing wooden soffit. If this is the case, you don’t need to worry about the anchorage of the soffit material, but you may still want to check the anchorage of the fascia cover as outlined below.
Check the connection between the wall and the soffit. If soffit panels are vinyl or aluminum, they can rotate or break loose due to wind.
Push the middle of the soffit panel and watch the trim. If the trim rotates there is probably no wood installed. If the trim doesn’t rotate, it probably has wood installed.
If it appears there is wood installed behind the trim, pull down on the trim and see if it is attached to the wood.
Check soffit panels to see if they are secure. Can they be moved?
Check to see if the soffit is connected to the eave.
Gently pull down on the fascia cover so that you can see the ends of the soffit panels. Sometimes soffit panels are nailed or stapled to the fascia board. Check to make sure staples are not corroded and are adequate.
A “good” fascia cover installation will have one tiny nail on the big face of the fascia cover once every 12 feet and on the bottom 2-in. edge, about every 12 in. Even this “good” fastening is not good enough in a hurricane unless the soffit panels are well fastened directly to the fascia board.
Steps for strengthening existing soffits:
When the soffit is in good condition and the length is less than or equal to 12 in., strengthen it rather than replace it.
Install powder coated color matched or stainless steel sheet-metal screws that will penetrate through both legs of the J or F channel supporting the fascia panels at the wall such that they create a pin connection through the fascia panels as shown in Figure 2. Install the screws at 12 in. spacing along the channel supporting the fascia panels.
Install powder coated color matched or stainless steel sharp pointed screws through the sub-fascia and soffit panel and embedded at least ¾ in. into the wood sub-fascia at the edge of the eave as shown in Figure 3. Install these screws at 12 in. spacing around the perimeter of the eave.
Apply a bead of polyurethane sealant (match to color of the wall or soffit or paint, as desired) along the joint between the wall and the track holding the soffit panels as shown in Figure 4.
Apply beads of polyurethane sealant in the grooves where the fascia panels butt up against the wall channel and the sub-fascia.
Installing New Soffits
This will be one of the most effective ways to mitigate many potential weaknesses
If you find that your soffit panels are not well attached and well supported, you can always have the existing materials removed and new soffits installed following the manufacturer’s recommendations for high wind installations.
Steps for installing new soffits:
Remove the existing soffit panels and re-install: Remove the existing soffit panels and label them so that they can be reinstalled in the same locations-Note: Lengths of soffits may vary around the house so it may be difficult to install some of the panels in a different location. Furthermore, there is a good chance that some or all of the material will need to be replaced, so make sure that it can be matched before it is removed. Any damaged soffit material should be replaced. Re-install soffit panels in accordance with the manufacturer’s high wind installation instructions, or, if the manufacturer is unknown, in accordance with Figure 1 above.
Strengthen the anchorage of existing soffit materials: When the existing vinyl or aluminum soffit system is in good condition and the nailing strips are not more than 12 inches apart, provide an attachment for soffit panels to all nailing strips or other wood supports (like the fascia or subfascia).
Gable End Soffit Vents
Soffits under overhangs at gable ends, if vented to the attic, are almost certain to allow water to enter attic spaces even in rather mild storms because there is no water dam to stop the wind driven rain. Not all overhangs at gable ends are actually vented to the attic. You can check easily by looking for daylight along the top edge of the gable end from within the attic. If you do see daylight, then you need to address this issue.
If the gable rake soffit vents are not required in order to comply with roof ventilation requirements, then there are two options:
- Remove the vented soffit material and reinstall a non-porous soffit material to the bottom of the outlookers in accordance with the manufacturer’s installation guidelines for high-wind areas.
- Plug the gaps from the inside with metal flashing and sealant. The flashing should be well attached and completely seal the openings.
Use sealant around the edges. An alternative would be to use wood blocking with caulk adhesive all around in lieu of the metal flashing.
© 2012 Insurance Institute for Business & Home Safety