Pepe's Piri Piri HQ

Exall Group have completed a full roof overclad at Pepe's Piri Piri's head office in Watford, Hertfordshire.

The existing roof was only around six years old, which surprises people when they hear it was leaking. Age wasn't the problem; the detailing was. A roof is only ever as good as the bits where it stops being a flat run of sheeting — and on this one, those bits hadn't been done properly.

The rooflights were the clearest example. Poorly formed upstands and weak flashing details meant water was finding its way in at almost every penetration. No amount of patching fixes a detail that was wrong from the day it went on.

Rather than strip a relatively young roof and put the client through the cost and disruption of a full replacement, we over-clad it. The new outer sheet goes on over the existing roof, and every detail — rooflights, penetrations, eaves, verges — is formed properly this time round. The building stayed in use throughout.

The gutters were relined with a new Sikaplan laminated gutter system. The laminated membrane is fully welded into a continuous, seamless lining, taking out the joints and laps that were the weak point before and giving a finish that will outlast the sheeting around it.

Detailing is where roofs fail and it's where the work goes. Get it right first time and the roof does its job quietly for decades. Get it wrong and you're back on site in six years, whatever the material cost.

Handed back watertight, properly detailed and good for the long term.