What a roof replacement costs around Philadelphia
Two quotes on the same house can be thousands of dollars apart, and it is almost never because one contractor is greedy. It is because the two numbers include different work — and on housing this old, the work that differs is nearly always hidden: what is under the covering, and what happens at the edges.
The lines that move the number
Layers first: code allows two, and on sixty-year-old suburban stock a third is a common find, which turns a recover into a full strip. Decking second, priced per sheet — and here comes the local wildcard. Anything roofed in slate a century ago sits on spaced sheathing: gapped boards that modern shingle cannot be nailed to. Sheeting over them is a real material and labour line, and a quote that never mentions it either has not looked or is planning to raise the price mid-job.
Then the details this housing makes likely. The porch or low-slope section, which needs different material than the main field and is the most commonly omitted item in a local quote. The party-wall tie-in on rows and twins. Chimney step and counter-flashing, replaced rather than reused, cut into the mortar rather than caulked to the brick. Valley metal, which decades of leaf load under a mature canopy has usually finished. And ventilation, which on a pre-1960 house often has to be created rather than corrected.
Why timing changes the quote
The working season here runs March into December — long by our standards — but that does not mean the calendar is open. Spring and early autumn are what everyone wants, and the specialist trades who handle slate, steep old framing and attached-house tie-ins are a small pool that books months ahead. The practical consequence: quotes gathered in January and February get the attention and the schedule choice, while a call in September gets whoever is free. On plat-built streets where a whole development is coming due at once, being a season ahead of the neighbours is worth real money.
Before you sign, make every bidder answer
- How many layers come off, and is disposal included?
- What is the per-sheet decking price, and what if the sheathing is spaced?
- Is the porch or low-slope roof included, and in what material?
- How does the new covering tie into an attached neighbour?
- Is chimney counter-flashing cut into the mortar, or caulked to the face?
- What exactly does the ventilation scope include?
Next step: Slate or shingle: the decision