Proposed new roof - lead or GRP?

[waveneygnome]

I am having a new roof built on a outhouse, which I hope to convert to habitable accommodation in a few years to come (my 10 yr project).

The roof is octagon shaped (8 sides) pitched to a point in the centre.

I have had structural engineering drawings made, a galvanized steel ring beam installed, and some chippy mates have helped me put up the timbers around a central newel post.

I have just finished cladding with 12.5mm of sitka spruce.

I was planning all along to finish in GRP to look like lead (polyroof 185), as I was under the impression that lead was 'really dear'.

Approx total area is 28m2.

The local GRPer has come round with a quote of £2600 inc vat. Polyroof supply a 20yr gtee......is it worth the paper its written on?

By chance I met the builders at our local church, and they introduced me to the lead roofer they have used on many ooccasions

He has now quoted me £6350 plus an extra £400 required to amend exiexistingmberwork to allow for venventilationHe offers a 20yr via the Lead Contractors Association.

So the difference between the two systems is £4100.

Which one would you go for?

I had not thought of the ventventilationues - is there anywhere I can read up about them?

Any views or alternatives greatly appreciated.

P.S. I don't think its the same lead that got knicked off the church last week....but its the same colour!

 

[Nige F]

that 20 year guarantee with lead assn. is just a fraction of the lifespan of the material . I`d ask him for a couple of jobs he`s done to look at. Gotta be the best option

 

[freddiemercurystwin]

First off I'd get a few more quotes, then you will know the prices you have been quoted are accurate

I would say if you expect to stay in your property for many years and you find the GRP unattractive (as do I IMO) and you can justify the extra cost then go for lead.

A fair bit on ventilation here: //www.diynot.com/forums/viewtopic.php?p=1378522#1378522

You could also consider zinc or copper which will both also give a very good lifespan.

 

[Cumbrianroofer30yrsexp]

Lead is expensive yes but it will last a life time.Can you afford to have it doen in lead?if the answer is yes then get it in lead but get other quotes but be carfull as leadwork is a specialist job and alot of roofers can only do basic leadwork.I was trained in leadwork by a plumber.Ask to see pics of completed lead work and customer contact details.Copper as mentioned is also acceptable and wont look out of place either unlike GRP.

 

[waveneygnome]

I feel like I am chasing my tail.

I have got two more quotes now.

Another quote for lead at £6650 +vat..............but no mention of me needing ventilation. When I raised it the guy look puzzled 'well I suppose you could have vents around the top if you really wanted it, but that extra'. Having looked at the diagrams on roof ventilation, I think I need a bit more that 'a few around the top'. Conclusion = not too confident in this firms ability.

Another GRP quote, recommended by the Polyroof the GRP supplier. He took one look at the roof and said....you really out to do it in lead...but I will quote if you want me to; you definitely need ventilation, we can create a 'warm roof', then put the GRP system on top........but it really ought to be done in lead. He said that if I just put GRP on the existing structure (as proposed by first GRP firm) it will be fine for a couple of years, then the decking boards will go mouldy/start to smell from all the condensation, then the GRP will crack. Conclusion = this chap seemed to know what he was taking about, and even though he does GRP for a living, would not specify it on this occassion.

I think its time to visit someone knowledgable and 'independent' from the actual covering material e.g architech/structural engineer?

Dizzy dog
WG

 

[hardmetalking]

I could do it in zinc for the same price as the GRP and give you a 60 year guarantee. I have many previous clients in Norfolk and would be happy to show my work first hand.
You even have the option of matching zinc gutters and downpipes at a very reasonable price.
If you email me the drawings with dimensions I can give you a free quote.
Hope this helps.

 

[chappers]

the poly roofer who said do it in lead says it all really, it won't last a lifetime but several if done properly and will look the business too

 

[waveneygnome]

Just an update.

Spoke to structural engineer & architech and agreed plan of action.

Had to take off ply deck, and add 50mm battens & relay ply deck (to increase ventilation and create a cold roof).

Worked loads of overtime and went for lead.

If I can I'll try and upload some pics.

I am really pleased with the result.

(Hardmetalking - if I had known about you earlier in the process I would definately have taken you up on you offer)