A slate roof inspection is not a walk around the yard with a clipboard. Done properly on an average house it takes two to four hours, and most of that time goes toward things that are easy to miss from a driveway: the underside of the deck, the condition of the nails holding each slate, the solder joints in a valley, whether a piece of flashing tucks up behind the slate above it or just sits on top of it with a bead of caulk.
Most homeowners call us after somebody else has already been out. Often that person spent fifteen minutes on the roof, quoted a full replacement, and could not say which slates were broken, where the water was actually entering, or what kind of stone was up there. That is not an inspection. That is a sales call with a ladder.
Below is the sequence our crews follow and what each step is meant to find. If you are hiring someone else, use it as a checklist. A roofer who skips three of these steps is guessing.
Step one: the ground survey with optics
We start on the ground, all the way around the house, with binoculars and a long lens. A slate roof read from forty feet away tells you things you cannot see standing on it, because from below you are looking at the plane of the roof edge on and small deviations jump out. What we are reading from the ground:
- Slipped slates. A slate that has dropped an inch or two out of its course is the signature of a failed nail. The stone itself is usually fine. One slipped slate in a field of two thousand is a repair. Forty scattered across one slope is a nail failure pattern, and that is a different conversation.
- Missing and broken slates. We mark the location of every one by course and by bay so we can find it again from above without hunting.
- Delamination. Some stone fails by splitting into sheets parallel to its face. From below, a delaminating slate looks slightly thicker at the exposed edge. A whole slope going that way at once means the stone is at the end of its service life, which for slate runs roughly 75 to 150 years depending on the quarry it came from.
- Sagging and wave. A dip in the ridge line or a soft wave across a slope points at the structure, not the roofing. Slate is heavy. A rafter that has been wet for twenty years will tell you so by the shape of the roof.
- Mortar and masonry. Chimney crowns, parapets, and the mortar joints a flashing is set into. A surprising share of what gets called a roof leak is water coming through a cracked crown or open joint above the flashing line.
We photograph all of it from the ground before anyone touches the roof, so there is a record of the condition we arrived to.
Step two: the attic and the underside of the deck
The attic is where a slate roof tells the truth. Water that entered years ago and dried is still visible on the sheathing as a stain with a hard edge. Active water is dark and often damp to the touch. The difference separates a problem you are living with from one that is ongoing.
In the attic we look for staining at rafters and sheathing, following any run of water uphill to find where it started. We check the nail points visible through open board sheathing, because rusted shanks show from underneath before the slate slips outside. We look at the deck material itself, since most slate roofs here are laid over board sheathing rather than plywood, and old boards can be sound in one bay and punky in the next. We check insulation for dark patches, which mark where water has been running. And we look at the chimney where it passes through, since staining on the masonry inside the attic puts the leak above that point.
If the attic is finished or inaccessible we say so in the report rather than pretending we saw it. That limits what any inspection can conclude, and you should be told so plainly.
Step three: on the roof, edges and valleys first
Access matters more on slate than on any other roof covering. We use hook ladders, roof jacks, or staging depending on the pitch and the condition of the stone, and we keep load off the field of the roof. Slate is brittle and breaks under point loading, so a careless inspection creates the very damage it was hired to find.
Eaves and rakes
The first two or three courses at the eave take the most water and the most ice. We check the starter course, the drip edge if there is one, and whether the bottom courses have been face nailed by a previous repair. Face nails in the exposed portion of a slate are a leak waiting to happen and a sign that somebody worked on this roof who did not know slate.
Valleys
Valleys fail first, because that is where the water volume is. We look at the metal itself, usually copper on an original roof, at the width of the open channel, and at solder joints and laps for cracks. Copper can serve for many decades but it does not last forever, and on a roof where the stone is still good the valley is often the thing that is worn out. We also look for debris packs, since a valley that holds leaves holds water.
Ridges and hips
Ridge slates are often bedded in mortar on older installations. We check whether that mortar is sound, whether the ridge has been replaced with something incompatible, and whether the top course underneath has been disturbed.
Step four: flashing detail and fastener sampling
Flashing is the most common source of leaks on an otherwise sound slate roof. We examine every penetration and every place the roof meets a wall: chimney base and step flashing, counterflashing set into the masonry, dormer cheeks, sidewall terminations, plumbing vents, and any bracket somebody has added over the years. What we want to know is whether the metal is layered so water runs over each piece in turn, or whether it has been sealed with caulk and roof cement, which fails in a few seasons and hides the failure while it happens. When we find that, the fix is proper slate roof flashing repair rather than anything to do with the stone.
Fastener sampling is the step most inspections skip. We lift a small number of slates in different areas of the roof with a slate ripper and look at the nails. Original nails may be cut iron, later ones galvanized steel, and on good restorations copper or stainless. If the nails in four sample locations are down to a thread of metal, the slates are being held up by friction and the next windy week will take some of them. That changes the recommendation completely, from spot repair to a plan for the whole slope. On the homes we see around Appomattox and the farm properties nearby, where a lot of roofs are eighty to a hundred years old, nail condition is often the deciding factor rather than the stone.
Step five: documentation, photos, and what you get
An inspection that ends with a verbal opinion is worth very little. When we finish a full slate roof inspection, you get photographs of each defect with enough context in the frame to tell where on the roof it is, a written description of what we found, an identification of the stone type and an estimate of remaining service life, a list of repairs separated into what needs doing now and what can wait, and notes on anything we could not access.
We also tell you what we did not find. If the roof is in good shape and the leak is coming from a cracked chimney crown, that is the report. If the stone has thirty years left but the valleys have five, you should know both numbers, because that shapes what you spend and when. Many roofs need nothing more than routine slate roof maintenance on a set schedule to keep going for decades.
Common questions
How long does a slate roof inspection take?
Two to four hours for a typical house, longer for a large roof, multiple dormers, or complicated masonry. If someone tells you they can inspect a slate roof in twenty minutes, they are looking at the parts you can see from a ladder at the eave.
Will the inspection damage my slate?
It should not, if it is done with proper access. Slate breaks from point loading, so walking the field of the roof in boots is the main risk. Hook ladders, roof jacks, and staging spread the load. We lift only a few slates for fastener sampling and we set them back with a slate hook rather than face nailing them.
Do I need an inspection if I do not have a leak?
An active leak means water has already been in the structure for a while. Most of the expensive damage we see on old slate roofs happened quietly under a valley or behind a chimney long before a stain reached a ceiling. Older housing stock in the region, including many of the homes where we do slate roof work in Roanoke and the surrounding neighborhoods, carries roofs well past the age where small failures start compounding.
Can a general roofing company inspect a slate roof?
Some can. Many cannot, and the tell is in the vocabulary. If the person on your roof cannot name the stone, does not mention the fasteners, and reaches for a tube of sealant, the inspection is not going to be useful to you.
Have your roof looked at properly
If you have a slipped slate, a stain on a ceiling, or just a roof old enough that nobody has looked at it in twenty years, a real inspection will tell you what you are dealing with before it becomes structural. We will give you the findings in writing with photographs, including the parts that are fine. Call +15555555555 to schedule an inspection.
