Overlay can work if…
- There is exactly one layer of old siding
- It is flat, tight and dry, with no soft spots
- You are installing vinyl, often over foam board
- Window and door trim can be extended to the new depth
Tear off if…
$1,000–$3,000 added
- There are already two layers
- Any wall shows soft spots, stains or bulges
- You are installing fiber cement or engineered wood
- Windows leak or have never been flashed
- Old wood siding has been patched many times
What overlay hides
The question on Reddit and in our estimates is the same: what is under there? On older Michiana homes we regularly find original wood siding under aluminum or vinyl, and sometimes asbestos-cement shingles. Under that there may be no house wrap at all, and windows that were never flashed. Covering it again leaves those problems in the wall for another 30 years.
- Rot. Wet sheathing keeps rotting under new siding. Replacing it costs $60–$100 per sheet when we can see it.
- Water management. New house wrap and window flashing are what keep a wall dry. They can only be done properly on a bare wall.
- Depth at windows. Two layers of siding sink windows into a deep pocket. The trim needs extending, or water and ice collect at the sill.
- Fastening. Nails have to reach solid wood. Through two layers of siding they often do not.
Old houses: lead paint and asbestos
Wood siding on homes built before 1978 may carry lead paint. Disturbing it is covered by the EPA lead renovation rule and needs lead-safe work practices. Asbestos-cement shingles are usually left in place and covered, or removed by a licensed abatement contractor; they should never be broken up by a siding crew. We check for both at the estimate.
| What | Price range |
|---|---|
| Old siding tear-off and disposal | $1,000–$3,000 per project |
| Rotted OSB sheathing replacement | $60–$100 per 4x8 sheet |
| Exterior trim replacement | $1,500–$4,000 per project |
The services involved
Questions people ask
Do I need to remove old siding before installing new siding?
Not always for vinyl over one flat, dry layer, but it is the better job. Removal costs more and takes a day or two longer, and in return you get new house wrap, flashed windows and any rotted sheathing replaced before it is covered for decades.
Can vinyl siding go over old wood siding?
Yes, if the wood is flat, solid and dry. Installers usually add foam board or furring strips first to give a flat surface and some insulation. If the wood is cupped, split or soft, it should come off, because the vinyl will follow every wave.
Should I be worried about what is under my old siding?
Worth checking, not worrying. Common finds on older homes are original wood siding, missing house wrap and unflashed windows, all of which are fixed during a tear-off. On pre-1978 homes, lead paint is handled with lead-safe practices, and asbestos-cement shingles are usually left in place and covered.