Tile vs Slate Roofing

The word tile is too broad for a proposal. Clay and concrete are different materials, and curved and flat profiles produce different details. State which one is being compared with slate. The National Park Service’s clay tile brief documents the importance of shape, texture, and historic detailing; it is guidance about clay tile, not a performance certificate for every concrete tile on sale.

Similarly, natural slate is stone rather than a single branded recipe. A comparison should identify the slate being proposed and the visual pattern it will create. NPS guidance treats roof patterns and details as part of a historic building’s character. Where that character matters, request a sample layout and photographs of comparable completed work before choosing between two names on a price sheet.

Sources: Preservation Brief 30: Historic Clay Tile Roofs; Preservation Brief 29: Historic Slate Roofs.

Ask for installed assembly weight using the actual specification, rather than a generic internet range. Include the covering, underlayment, battens where used, accessories, and retained materials. If switching coverings increases load or the framing condition is uncertain, establish suitability for the building. A roof that previously carried one tile profile has not thereby been evaluated for every other tile or slate.

Have bidders identify each slope, valley, roof-to-wall transition, and penetration on a marked plan. Request confirmation that the selected system suits those conditions. A porch or addition may need a separate covering even when the main roof accepts the chosen material. The comparison becomes much clearer when exceptions appear in the drawing and price rather than emerging after tear-off.

Consider a house whose curved clay roof is a defining feature and whose local roofers regularly repair that profile. Retaining tile is a reasonable starting preference if the roof needs replacement. Change the house to one designed around flat slate with a reliable slater nearby, and slate becomes the more natural starting point. These are design and service judgments, not claims that either covering is always superior.

Now suppose the preferred proposal has no clear route for replacement units or skilled repairs. Ask the contractor for a realistic small-repair scenario and the expected source of matching material. Preserve a labeled spare stock if recommended. A beautiful sample does not resolve future access, and the initial installer’s name is insufficient if that company does not undertake service work.

Request three distinct descriptions where an existing roof is involved: retain and repair, remove and relay suitable units if appropriate, and replace the covering. Require the contractor to explain why each is feasible or unsuitable. These are options to investigate, not interchangeable prescriptions. Deck condition, underlayment, attachment, and the quantity of damaged units determine what can actually be retained.

For complete replacements, align the access equipment, disposal, deck allowance, flashing metals, valleys, ridge and hip accessories, and cleanup. List any structural work separately. Avoid using a warranty term as the denominator in a cost-per-year calculation; the useful planning period should reflect the whole assembly and your ownership plan. Ask who pays labor when the covering remains sound but a detail needs repair.

Finish with a written selection record: exact material, approved appearance, permitted application, complete scope, maintenance contact, and reason for choosing it. If two options remain close, request a second comparable local proposal for each. Better-defined bids usually provide more value at that stage than another generic ranking of roofing materials.