What Does a Complete Re-Roof Include in Birkenhead?

“Complete re-roof” appears at the top of most quotations and is defined in almost none of them. The most useful way to pin it down is to stop thinking of a roof as a surface and start thinking of it as five systems stacked together, each doing a different job.

It also answers a question we hear constantly on Birkenhead's older terraces: why is it happening everywhere at once? Because three of the five systems are present across the whole roof and age at the same rate. When one goes, it goes generally.

System One: The Covering

Job: shed the great majority of the water.

The slates or tiles — the part everyone sees, and on a slate roof usually the longest-lived of the five. A complete re-roof either renews it or, where the existing slates are sound, strips and relays them.

• Existing covering stripped and, where relevant, sorted for re-use
• New covering laid to a fixing specification calculated for the address
• All fittings — ridge, hip, verge and valley components

System Two: Fixing and Support

Job: hold the covering in place.

Battens and fixings. Invisible, unreachable without stripping the covering, and the commonest first failure on an older roof. Nails corrode; battens split along the nail line or soften where water has been sitting.

• All old battens removed
• New treated, graded battens at the gauge the chosen covering requires — they carry printed markings you can read off the timber
• New fixings throughout, appropriate to the covering and the exposure
• Rafters, purlins and wall plates inspected while exposed, and defective timber replaced at a rate agreed in advance

That last item deserves emphasis. The strip is the only opportunity anyone will have to see the roof structure properly. Ask to be shown what is found, before it is covered up again.

System Three: The Secondary Barrier

Job: catch anything that gets past the covering.

The underlay. On older roofs this is bitumen felt, which embrittles and tears, particularly at the eaves. It is the difference between a slipped slate being an inconvenience and being a leak into the house — which is exactly why problems seem to appear suddenly and in several rooms.

• Old underlay removed entirely
• New breathable membrane across the whole roof, correctly lapped
• An eaves carrier or support tray so the membrane discharges into the gutter rather than behind it

System Four: Junctions and Edges

Job: weather every place where the roof meets something else.

Chimneys, abutments, valleys, ridges, hips, verges — and on a terrace, the party line. Statistically this is where roofs leak, not in the middle of a slope. It is also the system most often short-changed in a cheap quotation, because it is fiddly and does not show up in a square-metre rate.

• New lead to chimneys, abutments and any pipe penetration, at the correct code and in appropriately sized sheets
• Valleys properly formed
• Ridge and hip mechanically fixed rather than relying on mortar bedding
• Verges finished appropriately to the property
• The party-line junction weathered properly where only one half of a pair or terrace is being done
• Chimney repointing and flaunching, which is inexpensive while the scaffold is up

Lead sheets that are too long split from thermal movement, and mortar-bedded ridges crack and let tiles work loose. Both are predictable, and both are avoided by specifying properly rather than cheaply.

System Five: Ventilation and Thermal

Job: keep the roof space dry and the heat inside the house.

The system most often missing altogether on older roofs, because they relied on being draughty. Once you insulate a roof and put a membrane over it, air has to move through the space or moisture accumulates and the timbers suffer.

• Ventilation at the eaves, so air can enter
• Ventilation at the ridge or high level, so it can leave
• Insulation upgraded to current standards where the threshold is crossed
• Insulation kept clear of the eaves ventilation path, so one does not defeat the other

That last point matters. Insulation stuffed hard into the eaves blocks the airflow the roof needs, and the result is condensation on the underside of the membrane. It is a common fault and easily avoided with a proper eaves detail.

Why the Framing Helps

Read across the overlay row. It adds a covering's weight to a structure designed for one, leaves the two systems that most often failed exactly as they were, and hides the timbers so nobody can see what is happening to them.

What Is Normally Excluded

• Flat roofs over extensions, dormers or porches — a different trade, itemised separately
• Internal redecoration where an earlier leak has marked a ceiling
• Loft conversion work beyond what the regulations require
• Chimney removal, unless specifically quoted
• Solar panel removal and refitting, usually arranged with the panel installer

The Regulations, in Brief

Two separate systems. Planning: a like-for-like re-roof does not materially affect the external appearance of a building, so under section 55 of the Town and Country Planning Act 1990 it is not development at all and needs no permission. A visible change of covering can be a different matter, particularly inside a conservation area, where the test is applied more tightly.

Building regulations: where more than 50% of the roof's surface area is renewed, or the work forms part of a major renovation, regulation 23 of the Building Regulations 2010 requires the roof to be brought up to current thermal standards so far as that is technically, functionally and economically feasible — 0.16 W/(m²K) for a roof in an existing dwelling. A patch repair does not trigger it, and neither does a roof over unheated space such as a detached garage.

More New Roof Advice for Birkenhead

New roof installations in Birkenhead →
All new roof guides →
New Roof Installations Chester →