flat roofed garage

johnfw · Posted: Fri Jan 16, 2004 11:21 am Post Subject: flat roofed garage

my garage roof is boarded with 8x4 sheets of chipboard, the property is 26years old & the roof is the original one I believe we only moved in,in March 2000. given the porous nature of this product i'm suprised to see it used for this sort of external work is this usual or would you other materials?

Since the heavy rains of last year my roof has developed a leak and the moisture has quickly spread across the first third of the roof, I intend to to replace all the original boards and felting. can you you give me some product advice on the boarding & recomendations on felting,weather proofing the boards & the types of bitumin products to use? I know that the trade use hot pitch but I want to avoid that.

Many thanks

john

nstreet · Posted: Fri Jan 16, 2004 6:35 pm Post Subject:

I've never re-felted a roof yet but I am considering usung the cold lay product on this page, to reroof my porch (8'x10'). The site has some comprehensive manuals on how to lay the felt. Has anyone used this, if so can we have your comments. It may help both johnfw and myself out.

see this

masona · Posted: Fri Jan 16, 2004 8:02 pm Post Subject:

johnfw,

A lot depend how much you want to spend.

Is it a free standing garage or lean to type etc ? there are many ways of doing it,I will say it's best to get away from having bitumen flat roof.Have you thought of having industrial metal sheeting with a roof tiles at front, maybe a pitch roof or fibreglass roof ? I have use a lightweight metal sheeting tiles effect on my summerhouse,the picture on this forum somewhere ! If you decided to keep the flat roof then use exterior plywood.

nstreet,

Yes they are expensive than others but very good,very flexible and have a higher softening point when done correctly.Have you also consider a small low pitch roof ?

Bearing in mind you both will need building permission if you are going to altered the roof size but don't worry it's very straight forward.

GwaiLo · Posted: Sat Jan 17, 2004 1:31 am Post Subject:

Well, lets be honest given the price of felt roofing 26 years is a bargain.

If you want another bargain I would suggest that you remove the roofing felt and decking. Make sure there is not rot in the joists and renew the roof with 18mm WBP Plywood and a three layer high performance elastomeric felt system. If you approach one of the major felt manufacturers and use thier system (and have the work done by one of thier approved contractors) they will give you an insurance backed warranty (for workmanship and materials) for at leat 15 years.

Manufaturers I have used that spring to mind are:

Marley
Andersons
Erisco Bauder

__________________
This is not advice. Seek professional advice. I accept no liability errors or omissions.

IanP · Posted: Mon Jan 26, 2004 12:03 pm Post Subject: Cold Lay felt

I used a cold lay felt last spring and it worked perfectly.

Just make sure you don't do it on a very hot day, the felt gets a bit too soft to handle properly and the backing plastic gets a bit sticky. A warmish (20 degrees) dry spring day is the best time to do it.

towarmaster · Posted: Wed Apr 21, 2004 3:19 pm Post Subject:

If you have not already repaired your roof, then I would strongly recommend the use of an alternative product that far outlasts the life of felt.

A one sheet rubber membrane that stretches and contracts with atmospheric changes. Easy to fit!!!

Look this

jeds · Posted: Sat Apr 24, 2004 12:48 am Post Subject:

If you want a good quality durable job a 3 layer system with a mineral felt finish is best. I have used them all and found Tremco to be consistently good.

Contact your local technical rep and ask him/her to recommend 3 approved contractors.

Don't let anybody talk you into a single ply system such as Trocal or similar.

racinggood · Posted: Mon Aug 17, 2009 1:26 pm Post Subject: Re: flat roofed garage

johnfw wrote:

my garage roof is boarded with 8x4 sheets of chipboard, the property is 26years old & the roof is the original one I believe we only moved in,in March 2000. given the porous nature of this product i'm suprised to see it used for this sort of external work is this usual or would you other materials?

Since the heavy rains of last year my roof has developed a leak and the moisture has quickly spread across the first third of the roof, I intend to to replace all the original boards and felting. can you you give me some product advice on the boarding & recomendations on felting,weather proofing the boards & the types of bitumin products to use? I know that the trade use hot pitch but I want to avoid that.

Many thanks

john