Ridge tiles

[John]

I need my ridge tiles re-pointing. What should I be insisting on when getting a quote?

[george [dicegeorge]]

originally mine were pointed with lime mortar, which has crumbled with age and water, but underneath the joints was an inverted V of lead to take away any drips. The roofers repointed with portland cement, but without the lead V's.

Their roofing felt may have gone over the ridge, however.

[g]

[Dave Plowman (News)]

Pointing with ordinary mortar usually is a short term fix as there is movement between the ridge tiles and roof due to normal expansion, etc.

[John]

So what do you recommend? Remove - clean up - re-bed?? Any special type of mortar? House is 22 years old

[stuart noble]

I'd say a pva mortar (a 10% pva solution instead of water). It's performed well for me in such situations. I only wish my roofer had used it above the flashing. I've watched the pointing there crack and fall out over the years

[Phil L]

You don't have much choice. You either re-point the existing tiles with normal mortar, or get rid of the tiles and install dry ridges, these ridge tiles use no mortar and are clipped together with a plastic strip and then a stainless steel screw is driven through a stainless clamp at each joint.

If you choose the former, expect to have it re-pointed every 20 years or so.

[John]

Thanks for that - I wondered what it was that I had seen on a house nearby that has had a new roof. Some obvious fixings on each ridge tile. Just read the Manthorpe stuff on the internet. Not too convinced about the "comb" to seal against the pantiles.

[Phil L]

Just laid some on a large roof in Warrington. The 'mat' which has a combed edge, sits over the ridge and the tiles sit on the combed edge of the mat. It's combed to allow ventilation to the roof, and it's malleable so that it squashes down slightly when the tiles are screwed down, closing the gaps slightly so that wasps etc can't get in. It's dead easy to install, and I don't think it's very expensive neither.

[John]

Why is ventilation considered necessary - there wasn't any when the ridge tiles were set in mortar?

[george [dicegeorge]]

With modern warm houses and ceiling insulation and cold roofs warm moist air can trickle into the roof space and condense, rotting the wood over the years. [g]

[Andy Champ]

Tell me I'm misinterpreting this. Surely the roofers didn't remove your lead flashing and sell it?

Andy

[george [dicegeorge]]

They sold some lead from valleys, brought some back when I complained, don't know if there was any under the ridgetiles which they mortared in, there was lead under some of the ridge tiles I've taken off... [g]