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Building survey - issue with roof

(9 Posts)
user1489844432 Sat 18-Mar-17 13:47:27


I am FTB in the process of buying 3bed semi-detached (ca 1890) in Greater London.

I've just got a copy of building survey (level 3) and it reads like a horror story where the surveyor starts with statement saying that the property requires extensive repair and betterment and certainly after completing the process I will not have much left for any expensive repairs in the near future.

I have heard stories that surveyors are covering their backs and can potentially make it look far worse than it is but since I have not owned the house before I do not know how serious highlighted issues are.

I expected to see some issue with damp or electricity since it is not brand new but I got really concerned that roof covering and structure were marked as urgent. This house is currently rented out so I kind of was hoping that it will be in a good overall condition as the landlords needs to follow strict regulations. So definitely I did not expect the survey to highlight so many issues as serious/urgent (7 out of 17)

Can anyone please let me know if below issues with roof are serious and require immediate attention indeed? If so what would be the ballpark figure to get it fixed? I fully appreciate that no-one can say for sure without seeing it but as it stands now I am just clueless, so any help will be greatly appreciated!

Roof coverings
Findings of this property:
Coverings to the main roof structure are of interlocking concrete tiles, which as mentioned at D1 ‘Chimney stacks’ may be contemporary with the buildings’ first gas fired central heating system. It is likely that this would have been installed circa 1970.
These primary coverings overlay roofing/sarking felt, which as mentioned above is installed as a secondary defence against wind driven rain/snow/damp penetrating the building below.
Coverings to the front elevations’ bay structure are of plain concrete tiles, which might be contemporary with those to the main roof structure.
Laid to the rear extensions’ flat roof structure is bituminous felt, which has itself been covered in gravel.
In material condition, concrete coverings to the main roof structure remain consistent with my presumption over their age. These are perfectly serviceable for some years to come.
At eaves height to the roofs’ hips, hip irons have been installed to better support hip tiles. These metal fixings remain generally satisfactory in their condition, being free of any significant displacement or corrosion.
A verge is formed at the rear projections’ gabled elevation. Where verges are formed, high winds have been known to strip coverings from roof structures. In order to prevent this happening, this verge has been detailed with mortar, under cloaks supporting the mortar mix. Commonly found to deteriorate in their condition, mortar to this roofs’ verge remains generally satisfactory in its’ condition, the verge free of any notable or concerning defects.
As mentioned at ‘Limitations to inspection’, I was not able to inspect a valley formed between transversely and longitudinally orientated parts of the main roof structure. Valleys such as this one are prone to failure, the collection of leaf and other debris being a contributing cause. Whilst I was not able to inspect the valleys’ external parts, I could see that it is not currently leaking, this determination possible after having inspected the roof void/stricture.
Also having inspected the roof void/structure was I able to inspect roofing/sarking felt laid beneath primary coverings to the roof. This is showing clear signs of age related fatigue, sagging at several locations. Unfortunately I also found that the felt has been holed. Where damaged/holed the felt cannot perform its’ purpose and the prevention of penetrating damp is wholly reliant upon the good condition of primary coverings to the roof.
Lichen was noted to contaminate roof coverings. Although a little unsightly, this is not thought particularly deleterious to their fabric, its’ removal not an urgent matter.
Where moss establishes upon concrete roof coverings, this is also not particularly deleterious to their fabric, however it will inevitably have adverse consequences to other parts of the building. See E3 ‘Rainwater pipes and gutters’.
As discussed at my ‘Introduction’, where concrete coverings replace lighter coverings such as slates, which I suspect were this roofs’ original coverings, their additional weight can cause the roof structure to dish/distort. From ground level I could see that exactly this has occurred, distortion/dishing also identified to the roofs’ foremost hip. Please see E1 ‘Roof structure’ in this regard.

In their material condition, coverings to the front elevations’ bay structure very much reflect those to the main building, as do hip irons installed here also.
Where coverings to the bays’ roof structure meet with the main buildings’ front elevation, to form a watertight abutment a tiled mortar fillet has been installed. Mortar, in this use, is not considered a good longterm material. Being prone to thermal expansion/contraction and to failure, those tiles have been installed to mitigate this problem. Although thought to improve the details performance, a tiled mortar fillet will never be as robust or long lived as lead flashings, which are considered most appropriate. Whilst nothing was found to suggest that the mortar fillet is currently leaking, you should foresee this possibility, lead flashings to then replace the mortar.
Felt coverings to the buildings’ flat roofed single story extension, as mentioned above, have themselves been covered in gravel.
Where meeting with a parapet wall to the roofs’ left hand side, straight chased lead flashings have been dressed into the masonry and then laid over an up-stand to felt coverings. Although it does not appear that an adequate timber fillet has been installed beneath the felt, this to provide for two forty five degree turns into the up-stand rather than one at ninety degrees, the lead detailing over is thought good practice.
Where meeting with the rear projections’ external wall, felt coverings to the extensions’ roof are less well detailed. It is here that the felt is simply dressed up the wall and then chased into masonry. Where chased into the wall, mortar pointing has since failed and fallen away. The renewal of this mortar is required.
Gravel laid to the roof does not comprehensively cover the felt, exposed areas clearly visible. At the roofs’ rear verge this exposed felt has much deteriorated in its’ condition, coverings to this roof consequently very close to the end of their effective lifespan.
With an average lifespan of circa fifteen years I suspect that felt coverings to the rear extension will fail at any time, their renewal something you must budget for.


Roof structure
Findings of this property:
The original roof structure is of a traditional timber frame, this one likely to have incorporated such elements a ridge board, common rafters, hip rafters, hip jacks, valley rafter, valley jacks, purlins, struts, spreader plates, binders, ceiling joists and wall plates.
As mentioned at D2 ‘Roof coverings’, when viewed with the use of binoculars from ground level and within the curtilage of the property or from adjoining public thoroughfares/land, slopes to the main roof structure revealed some undulations, these most likely the result of additional weight imposed to the structure by much heavier coverings now laid over.
It does appear that some consideration has been given to the roofs’ additional loading, thick set timbers since installed across ceiling joists and supporting props to the roofs’ purlins. Evidencing their more recent installation, this possibly undertaken during or just after the roofs’ re-covering, is the fact that these heavy set timbers extend over both partially removed chimney breasts. Also retrospectively installed and to further strengthen the roof structure are collar tiles.
In addition to the aforementioned additional timbers to the roof, it also seems that certain timbers have more recently been renewed. Certainly at the roofs’ front slope horizontally orientated timbers bearing to ceiling joists and supporting notched rafter ends have been renewed. These works are not comprehensive, older timbers remaining in situ and much deteriorated in condition.
Although the roof and its’ present coverings are longstanding, it is quite possible that the structure remains inadequately specified for those heavy concrete tiles over. Only a structural engineer would be in a position to determine this. I would suggest it prudent to have such a professional inspect this roof, recommendations to be incorporated within a written report to be provided.
I found no significant rot to roof timbers nor evidence suggesting any ongoing infestation by wood boring insects, however my inspection was very limited. Given this buildings’ age, it is reasonable to assume that it will have suffered both of these problems in the past. It is also possible that both may be ongoing but concealed from view. For this reason I must strongly recommend that you have all timbers to the building inspected by a specialist contractor. To seek such a contractor you might contact the Property Care Association.
Insulation to the roof structure, this being quilt laid between ceiling joists, is wholly inadequate in its’ depth and should be increased to at least 300mm. Such works will inevitably elevate levels of relative humidity within the roof void, thereby promoting condensation damp and mould spores. I found that numerous timbers to the roof are already contaminated by mould, this illustrating high humidity and the roofs’ inadequate ventilation. In this regard I would refer you back to my ‘Introduction’ and to that subsection headed ‘Ventilation and insulation’ in particular.

wowfudge Sat 18-Mar-17 16:53:28

My goodness that is a very long post. So there is some work which you should think about getting done sooner rather than later and you should budget for replacing the roof in the next few years because the tiles are too heavy for the roof structure. So in your position I'd get a ball park figure for replacing the roof and take it from there.

Villagernumber9 Sat 18-Mar-17 19:04:12

The flat roof is covered in felt, which isn't very good. It should be a waterproof membrane sealed properly. Felt is a cheap and quick way of doing it, but, even the best felt will only last about 15 years.
The main roof has concrete tiles on, which only last about 60 years.
If you can go back and look in the attic, you can see the condition of the felt underneath the tiles. If it looks brickle, the whole roof might need doing I'm afraid.
Might be more expensive in London but, you're looking at at least £10,000.

Villagernumber9 Sat 18-Mar-17 19:13:19

Just read more of your essay. The roof timbers have signs of rot and the ceiling joists are inadequate.
You would be looking at a bill of at least £30,000.
I would give this house a very wide birth.

wowfudge Sat 18-Mar-17 20:48:32

Villager unless you are a roofer, you can't know how much the work will cost. And as the OP is buying in the London area that could well be a drop in the ocean relatively.

Villagernumber9 Sat 18-Mar-17 21:06:32

Wowfudge. I did two years up and down ladders doing roofing and I did say that it might be more expensive in London. Also done three and a half years fitting windows and doors.

SilverHawk Sat 18-Mar-17 21:16:15

I must admit that it looks very alarming at the first skim through. However, we had a very similar report on our first house. The main point is that slate or clay tiles are lighter than concrete tiles, therefore the roof timbers need reinforcing. It sound as if this has been done but perhaps not up to current standards.
The other thing that is mentioned but may also go under another name is wall strapping, where the roof has been too heavy.
What is odd are the comments about insulation. why have more insulation and more ventilation. Is that rather self defeating? I don't know.

SilverHawk Sat 18-Mar-17 21:19:07

Where you say collar tiles, you should read it as collar ties.

bilbodog Sat 18-Mar-17 22:41:02

It is suggested you get a structural engineer to look at the roof properly to see if it is suffering from the weight of the concrete tiles - that seems to be the worst part and if he agrees the house needs reroofing then get quotes from a couple of roofing companys and whilst you are at it replace tiles with slate which is probably what it had originally. You might be able to renegotiate the price of the house if they have had it done badly. If you dont have much money to spare you may well have to pull out and look for a house which needs less work.

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