A
J Hooper Roofing Specialists
Please Call: 07956 364536
01992 464131
Andrew1Hooper@btinternet.com
Roof flashings are one of the main causes of roof leaks, the job of roof flashings are
to form a sealed bridge between two things, this can be parapits walls, dormas, roof window, flat roofs, chimney stacks and
many more. One of the most common cause of a roof leaks is when these flashings break down which can be caused by many
factors.
Cement fillets, dentals and Lead Flashings: cement fillets
are still on many properties and can form a good seal but the problem now days is with heated homes and shrinking
timbers which cause movement in the roof. Many years ago this was not a problem and the roof would be layed to the wall abutment
and a cement fillet would be tilted at a 45 degree angle to roof and wall, this would often have tiled coloured dentals layed
into in to make the same colour as the roof. This type of seal would work very well until the roof moved which
would then crack the fillet away from the parapit, chimney stack etc and cause water to penitrate down the wall and into the
property. This problem with roof fillets has been overcome by the introduction of of roof flashings, although roof flashings
are mainly Lead there are also Zinc flashing, fibreglass flashing, felt flashing and probably more which I haven't used.
The Lead flashing type is by far the most popular choice but of recent time with the high price of metal and the possibility
of theft other materails have started to be used like fibreglass etc. The main benifit of a roof flash is
that it is attached to the wall but not the roof allowing the roof to move without breaking the flashings. Slate flashings
and flat tile flashings employ the help of soakers, these soakers are layed on each tile or slate as the roof is layed to
stop water traveling down the back of the slate or tile as it travels down the roof. The the cover flashing is installed,
this is chased into the wall either straight or stepped into the brickwork, they both offer the same protection but
if the brickwork will allow stepped flashing look far nicer and more traditional and is the one I enjoy doing most as it is
nice to admire your work, Instalation of these is by first chasing out either with a grinder if straight or by hand if stepped.
Normally for this 6" or 7" Lead would be used which would be cut into 4ft length then cut to steps and each step
bent to go into brickwork joint by min 1 inch, this is then Lead clipped or nailed if possible, dressed to wall and pointed
with a strong 3/1 mix.

Roof Valleys: Roof valleys are another common
problem with roof leaks, the roof valley is a point where two roof slopes meet like a dorma or an angle in the building which
could be an extension etc. again roof valley's are made of many materials Lead, Zinc, Copper, Felt, Fibreglass and
I'm sure many more. The best quality roof valley is always thought to be Lead because of its long life and durrability
but the main draw back is cost and if there are lots of valley's to be installed like a building site Fibreglass or Zinc
are often used. I alway recommend to my customers when we are installing a new roof not to skimp on this area of the
roof and go for the Lead because being a colletive place the valley where water collects it can be a nasty problem if
it leaks in the future and needs replacing. Replacing roof valley's is more difficult with slate roof's as the
slates are nailed and we need to use a special tool to free the slates to get the old valley out and fit the new valley, once
the new valley is fitted the slates are re-fitted and clip in place. With tiled valley's the tiles can be lifted
and the valley replacement carried out, when the tiles are relays and cut to the valley if needed it will require cement to
be pointed between the valley and tile to seal the gap and again this should be a strong 3/1 mix.

LEAD FLAT ROOF: Many bay roofs, small dormas and gutter
valleys us Lead, mainly these roofs are on public building or are listed, due to the expence many private properties opted
for the more cost effective and practical option of high performance felts, Lead roofs will give a very long life span
but has to be weighed up against the cost.

Today with sky high metal prices Lead theft has become very popular, although
it is imposible to completely protect against this type of theft it can be made more difficult with certain measures,
below is The Campus Church in Welwyn Garden City that was the target of Lead theft durring the summer where the Lead flashings
where taken from the dormas.

Please call on the above number for a Free Quote on any roof related problem