Page 118 - 2018 National Home Improvement

2018 National Home Improvement Estimator, All Rights Reserved Page 95

New Siding Over Old?
If the building has only one layer of siding, and if that siding is sound (no decay problem), consider
applying new siding over the old. This offers several advantages. First, you avoid the cost of demolition
and disposal. Second, the extra layer of wall cover adds at least some insulation value. And third,
installing siding over siding isn’t much more effort than installing siding over sheathing.

In some cases, removing the old siding is the best choice. If wood siding has decayed to the point
where it won’t hold a nail, you could try using longer nails to attach it right into the sheathing, but it’s
probably a candidate for tear-off. Mineral siding fractures into pieces when nailed. It’s easier to remove
mineral siding than to try to nail through it. Also, if the home already has two layers of siding, it’s
probably best to do a tear-off.

Trim around windows and doors needs special attention when applying new siding over old. Extra trim is
needed to compensate for the added wall thickness. Window sills aren’t a problem. Generally, sills
extend well beyond the existing siding in older homes. Look back at Figure 6-1. But if the window
casing is nearly flush with existing siding, some type of extension molding will be needed. Build up the
casing with an extra thickness of trim, as shown in Figure 6-2. You’ll probably need a wider drip cap at
the top of the window. If the drip cap is in good condition and can be removed in one piece, extend the
cap by fitting a block where the cap was. Then re-nail the cap over the block. Compare Figure 6-3A
(before) and Figure 6-3B (after). Building out trim on windows and doors is usually easier when vertical
siding is applied over horizontal siding.

Rather than build up the depth of window casing, you could add a wider trim piece at the edge of
existing trim. See Figure 6-4. A wider drip cap will also be required. Extend exterior door trim in the
same way.