This valley, as you can see from the photo, has the felt rotting through water penetration. The reason for this are the battens are on top of the fibreglass valley. The cement is then touching the battens, drawing in the water, rotting the battens and the felt.

This valley is of lead. In this case, which is quite common, the lead has been rolled out in one piece, where it is cracking and splitting under its own weight. Lead valley should not be rolled out in more than 1.5 meter pieces.

In this valley, it is having felt replaced length wise. The problem here was valley felt laid incorrectly.

This is an example of a failed fibreglass valley to a slate roof.

This valley has had a few repairs already, and it is still continuing to fail. The whole valley needs to be removed and replaced.

This is an example of a racking verge; in this case it did have a dry verge fitted. The dry verge had been blocked by leafs from an overhanging tree, sending the water passed the verge and onto the felt and batten, rotting the battens and the felt.

Racking verges are a difficult problem; if the roof has a more extreme rack in the verge it is better to use guttering. In most cases dry verge will do.

A raking verge should be treated as a valley.

Water penetration to the ladder truss end.

In this case the barge board end has dropped.

If water is getting under the tiles or slates it will rot the felt and possibly the rafters, causing structural damage.

Leaving a problem like this is going to cause damage in the long term, increasing the cost five fold.

In some cases Felt support trays can be placed under the existing felt and this is sufficient so long as the perished felt is not to far up the roof.

This image is of rotting felt on the eve, as you can see the felt has rotted through. One of two things can happen in the house here, if there is a sofit and a cavity wall, the water will penetrate above the window or door below. If there is no sofit and cavity wall the water will come through the corners of the sealing.

Water penetration at abutment wall. The lead was not cut deep enough.

Looking at this stack with the plants growing out of the perbs and beds of the bricks, moisture is holding in the black mortar which is holding moisture. If the plants are not racked out and the stack re-pointed, the bricks will be pushed apart making the whole stack unstable and dangerous.

Pointing around cowls or pots should be maintained or it makes the pots and cowls unstable and damp to the chimney breast wall, upstairs and down.

Missing pots speak for themselves. The birds nest inside and the water is going down that hole and coming out as damp in the ceilings, walls or fireplaces.

The same as with missing pots, with open pots the water is going somewhere. Cowls should be fitted.

Most leaks to chimney stacks are actually the water coming through where pots are missing or left open, and not as most people assume, through the lead.

This is top coat, to fiberglass flat roof flaking away from fiberglass undercoat. This may not coarse a leak, but doesnt look good.

Chimney stack to fibreglass flat roof. Lead to front apron and to side abutment has been fiberglassed over. Lead should be removed, fiberglass put up walls of stack and lead ontop. What has happened here is the fiberglass has cracked around the lead and the water has gone under the lead and fiberglass.

This roof here has had the old slates from the main left on top and not cleared away. The boiler pipe was not ceiled correctly causing a leak into the boiler. This roof was surfaced.

The above resurfaced in fibreglass covering.