Rosemary Tiled Roof

[SharonG]

We have a large Victorian Semi built in about 1910 which has the original roof tiled with Rosemary Tiles with no underfelt. Most of the roof has backpointing which I presume is also original and this is missing in a few places where you can see tiny *****s of daylight through. The roof appears watertight and has stayed on (touch wood) so far through all the recent gales and storms we have had.

My question is - after how long would it be prudent to have the roof completely redone and what would be a rough estimate ? I appreciate I have no sizing etc and this will be dificult to estimate.

Im concerned that it is likely to cost a fortune ! Does it matter that there is no underfelt - would underfelting make the house warmer ? The loft is currently insulated and with central heating on the house is warm but Im also concerned that maybe our heating bill will be through the roof (no pun intended) as the roof may be just soaking the heat up.

 

[MdB]

You need to worry about heat getting from your house into the roof space and don't worry about heat being lost through the tiles.

My house has very little ventilation in the loft space and suffers a bit from condensation so I'm looking at adding ventilation to it (lapvent looks like a good idea). I have read elsewhere that as long as there is no water coming in, it is difficult to have too much ventilation in a loft space.

I would worry about rain being blown up the gaps in your tiles more than anything else. You say that the roof is watertight so I wouldn't worry as long as this is the case.

I would also be interested in the cost of lifting tiles and replacing felt as ours is on the way out. Has anybody got any guide as to the sorts of costs involved?

 

[Gervase]

MdB's right - if your roof is sound and you've got adequate insulation on the ceilings (at least 100mm of rockwool or equivalent), don't worry about not having felt.
Prices for roofing vary hugely, but to strip, felt, batten and relay a simple pitched slate roof with no hips or dormers on a three-bedroomed detached house round here costs around £4,000, assuming a 10 per cent loss on the old slates (which is good going if they're beginning to show their age). For more affluent areas, I reckon you'd be looking at nearer £6,000 for a straightforward job (and obviously more if you've got lots of valleys, odd angles, dormer and hips).
You need to choose your roofer carefully, as a lot of them don't like reusing slates, and will come up with all sorts of excuses to get you to use new slates, fake slates or tiles (and the dodgier ones then sell off your old slates for over a quid apiece!).

 

[MdB]

Thanks for that Gervase, useful to know.

The current tiles are asbestos fake slate tiles fitted in the 1970s of which two or three have slipped due to either nail rot or poor fitting in the first place. The current felt has the odd hole in it but rain doesn't seem to have made it way in. I fitted a couple of extra bulbs into the loft space this weekend so I'll be able to give it a good inspection shortly to see exactly what condition it is in. So far I have noticed there is woodworm (unknown vintage) in some of the A frames and some interesting bodges in the woodwork but it is in better nick than I had thought.

The main issue is that the roof will need extending when we put an extra layer on the front wall. This will require extra tiles and a lot of disruption to the roof so it may be worth getting it put straight at the same time.

I would like to have real slates fitted instead of the asbestos tiles but I'm not sure the current roof beams will be strong enough to support this. I work next to a roofer (flat roofs only unfortunately) so I'll speak to them about it.

 

[yoofookinwah]

We had a quote for 6 grand to completely remove the slates and replace with felt batons and more up to date tiles on our Victorian terraced house.

I mentioned the Victorian timbers would not hold the new heavier style tile and reuse the existing replacing those that have worn away.

Our house is over three floors

 

[SharonG]

Thanks for the advice. Yes roof appears to be watertight even after all these gales and storms.

We do have loft insulation which does also appear quite old so were thinking of having this replaced anyway.

But this puts my mind at rest a little !

 

[MdB]

We do have loft insulation which does also appear quite old so were thinking of having this replaced anyway.

Unless you have a good reason to get rid of the old stuff, just put new stuff on top of the old. You might as well keep the benefit it gives at the moment.