Metal Over an Existing Shingle Roof

What has to be true

• The existing roof is dry, adhered and not already a second layer — code limits how many layers a roof may carry
• The deck is sound, which can only be known by inspection rather than assumption
• The existing surface is flat enough that panels will not telegraph every ridge and cupped shingle
• The system being installed is designed for recover, typically with battens or a furring arrangement
• The jurisdiction permits it for your assembly, which we confirm at permit rather than guess

What you give up

The deck inspection. Across Sacramento County, roughly 37% of permitted re-roofs involve sheathing, dry rot or structural work — and a recover is specifically the decision not to look.

You also lose the chance to close old penetrations properly, to correct ventilation, and to replace underlayment. On a forty-year roof system, giving those up to save tear-off cost is poor value.

When we will recommend it

• Outbuildings, shops and agricultural structures where the deck is visible from underneath
• A sound single-layer roof with verified dry sheathing and a documented reason to avoid tear-off
• Stone-coated steel systems explicitly designed for batten recover over one layer

When we will not

Any roof with evidence of past leaks, two existing layers, soft spots underfoot, or a ceiling stain anywhere in the house. Putting a forty-year roof over an unknown deck is the one decision in this trade you cannot revisit cheaply.

Common questions