DIY Reroof

paperclap

Hi all,

Long and short of it, we’ve been having some roof leaks. Now, I’m not suggesting I will carry out a reroof. If our old felt-less roof holds out, even better 

I’m asking the below questions to better prepare myself should I need to in the near future.

Our roof is a 30-35 degree pitch, covered in concrete Redland 49 (granular) tiles. Our ridge and hips are using standard wet system (tiles bedded in mortar). We are semi-detached. Our tiles connect with our neighbour’s roof.

https://redland.co.uk/products/profile-range/redland-49

Tiles
As mentioned above, we currently have concrete Redland 49 (granular) tiles. With planning permission, my neighbour’s roof, etc in mind, what are the limitations with regards to new tiles? Can we change the tile altogether (to say, slate)? If not, can we change the colour? Can we change the finish (granular vs smooth)?

Tiles: Granular vs Smooth
Other than aesthetics, what are the differences? Longevity? Porous vs impervious? Water runoff? UV protection? Protection against moss buildup?

Vent Tiles
Are they required, or even all that beneficial? Would soffit ventilation and natural gaps (creating “air leaks”) through the tiles suffice?

Batten Gauge / Tile Headlap
Is there a discussion to be had about decreasing the batten gauge (thus increasing tile headlap), so as to further circumvent the ingress of water in heavy rain and heavy wind conditions? For example, increasing the roof’s rows of tiles by one row. This however, may not work with our neighbour’s tile layout. Anywho, should it be possible, is this unnecessarily adding weight to the roof?

Dry Ridge/Hip System vs Wet Ridge/Hip System
It appears a dry system is becoming increasingly popular. Though, in comparison to the wet system, they’ve not got the years in to be “tried and tested”. Or, have they? What are your thoughts on the two options?

Breathable Membrane
Is DuPont Tyvek still the best performing breathable membrane out there? There seem to be other top products out there, such as from Klober and Cromar. It seems a lot of these membranes have different properties to suit different requirements. For example, some are more durable but less breathable. Others are lighter weight but more breathable.

As always, thank you for all your input.

FreeBear

laurencewhymark said: Dry Ridge/Hip System vs Wet Ridge/Hip System
It appears a dry system is becoming increasingly popular. Though, in comparison to the wet system, they’ve not got the years in to be “tried and tested”. Or, have they? What are your thoughts on the two options?

Dry ridge is quick & cheap for roofers to fit, but.... Speaking to a local roofer, he tells me that he is being called out to properties that had dry ridge fitted ~10y ago and is having to replace the lot. Plastic has a limited life span, so the short life span kinda fits in. Done properly, a mortared ridge will last 100y or more. Best case for plastic, 25 years.

paperclap

FreeBear said:

 laurencewhymark said: Dry Ridge/Hip System vs Wet Ridge/Hip System
It appears a dry system is becoming increasingly popular. Though, in comparison to the wet system, they’ve not got the years in to be “tried and tested”. Or, have they? What are your thoughts on the two options?

Dry ridge is quick & cheap for roofers to fit, but.... Speaking to a local roofer, he tells me that he is being called out to properties that had dry ridge fitted ~10y ago and is having to replace the lot. Plastic has a limited life span, so the short life span kinda fits in. Done properly, a mortared ridge will last 100y or more. Best case for plastic, 25 years.

Thanks FreeBear.

That was my thinking too, but wasn’t sure if the technology had “come along way”.

What were the reasons for the failure(s) though?

NSG666

Breathable membrane - if you have this it possibly negates the need for any further ventilation. The membrane itself is waterproof but once the tiles are in place, the only time the membrane should get wet is if there is a problem with say a cracked tile. I've worked in many properties that don't have any felt or membrane at all.

Slate - costs a small fortune for the good stuff and you need a good roofer who will sort it prior to fitting.

Colour - subject to local restrictions. When I was replacing mine the roofer told me the existing were brown but had faded. Once delivered it was obvious that the old tiles were in fact grey! But the brown looks ok to me. My next door neighbour has just done his with dark (almost black) grey tiles.

Mine are Sandtoft Lindum same as removed but neighbour has retro-fitted with something that looks like Marley Mendip and next door to them are having Marley Modern. I had dry ridges and verges but one thing I do like about next door's verges are moulded tiles rather than the plastic ones.

stuart45

laurencewhymark said:

FreeBear said:

 laurencewhymark said: Dry Ridge/Hip System vs Wet Ridge/Hip System
It appears a dry system is becoming increasingly popular. Though, in comparison to the wet system, they’ve not got the years in to be “tried and tested”. Or, have they? What are your thoughts on the two options?

Dry ridge is quick & cheap for roofers to fit, but.... Speaking to a local roofer, he tells me that he is being called out to properties that had dry ridge fitted ~10y ago and is having to replace the lot. Plastic has a limited life span, so the short life span kinda fits in. Done properly, a mortared ridge will last 100y or more. Best case for plastic, 25 years.

Thanks FreeBear.

That was my thinking too, but wasn’t sure if the technology had “come along way”.

What were the reasons for the failure(s) though?

You don't have to have plastic with a dry ridge system. New builds have a dry ridge system now because of NHBC guidance. The roof on a new build settles  and can fracture the cement. This is not an issue on a reroof. 
I've always done a wet ridge, although roofing isn't my trade and haven't done it on new builds.
There is the option of a hybrid ridge which is mechanically fixed but has mortar as well to give a traditional look.
If you have 3 or 4 inches headlap on a 49 at a 30 pitch that will be fine.
Remember you will have a new membrane under.