roofing question

[Pford75]

We have a single storey clay-lump annexe to the main house which was originally an outbuilding and was adjoined somewhere around 1830 when the house was extended.

Whilst the house is slated, this single storey (and all other outbuildings) have black glazed clay tiles. A few tiles have been slipping and the roof was leaking, so removed some tiles and had a look.

Thing is, there are no battens at all! The roof under the tiles has laths nailed across the rafters (on the outside, not the inside for a previous plaster ceiling). They appear 100% clean and not plastered at any stage. So, the problem is that there is nowhere for the tiles to 'hook' onto.

I can't batten without removing the laths - can anyone suggest another way of fixing the tiles? Also, I was thinking of felting under the tiles (experience tells me that one small leak wrecks the ceiling below)....any guidance on this?

 

[middi]

If it is understood correctly, the existing tiles are all holding and resting on external laths nailed across the roof rafters.

If this is the case, after all those years it should be no surprise that there are signs of deterioration to the roof generally.

There are two ways you can approach the situation.

1)...........Repair and replace like for like in order to keep the status quo,as was probably originally intended to be well ventilated for animal shelter etc....

2)...........Re-roof using new battens, breathing membrane and insulate in order to be used as habitable and heated occupation.

I would not hesitate to opt for the second option.

 

[Penners]

I would not hesitate to opt for the second option.

Me neither.

 

[Pford75]

Thanks for the advice - will have a think about it. Hadn't considered that the roof structure was a legacy of it's previous role as an 'outbuilding'. Appreciate the input!

 

[NT]

I would definitely be keen to avoid the 2nd option. Bear in mind this roof, despite its eyebrow raising construction, has served well for around 170 years now, and quite likely longer. It would be a shame to rip out the character of a roof that has lasted very well indeed, is clearly an unusual character, and has nothing more than a minor repair needed. I would want to repair it as closely to original as possible.

Insulation can be added below the rafters if needed, but more often insulation on the loft floor is the order of the day.

How to fix the tiles in place I couldnt suggest without a look at both tiles and woodwork, but looking at the existing roofing should show how its been done. And whatever that method is, 170 years says it clearly does work.


NT

 

[Penners]

There seems to be no suggestion that hanging the tiles on laths, instead of battens, was the original method of roofing. All we know is that it's been there for some indeterminate length of time. And "old" doesn't always mean "high quality"! In any event, tiles are now slipping and the roof is leaking.

In my view there comes a time when pragmatism must apply, and this is one of those times. Above all else (metaphorically and actually!) a building needs a good roof. If I was going to spend time and money creating a home underneath that roof, I would want it properly felted and battened, as Middi said.

 

[Pford75]

The tiles themselves look to be much more recent than the building. The building itself is 1780!

It's clear that the tiles were never meant as the original roof covering, since they have nothing to grip onto, have large gaps in some places and this in turn has allowed water to run onto the clay-lump wall.

My priority is keeping the clay lump dry and this probably means that I'll look to felt underneath. I will however be re-using all of the tiles and simply re-battening first

 

[Nemesis]

Now I'm confused - I rather thought that laths and battens were much the same thing!

Are the glazed tiles plain or of pantile type?

However - the trad alternative to felting is lime, the modern alternative is breathable membrane.

If this was my roof - - I'd seek some further advice via the SPAB free helpline, see what is suggested.

http://www.spab.org.uk


http://www.spab.org.uk/publications_Q&A_pantiles.html


http://www.buildingconservation.com/articles/pdf_roofsbreathe/roofsbreathe.pdf


http://www.buildingconservation.com/articles/roofvent/roofvent.htm


.

 

[Penners]

Now I'm confused - I rather thought that laths and battens were much the same thing!

Oh come on, Nemesis! I think you're a wee bit more knowledgeable than that! :wink:

Laths and battens are the same thing in the same way that a pencil and a tree are the same!

It's a question of thickness, hence strength and durability.

However, I do agree about a breathable membrane. I used the word "felt" as lazy shorthand.

 

[Nemesis]

Oop north, they are called laths!

Roofing laths as opposed to laths which you plaster on top of.


http://www.stoneroof.org.uk/gloss.html

 

[Pford75]

Battens sit proud of the surface (and allow the tiles to be 'hung' from them) whereas the laths are packed tightly against each other and therefore leave no means for 'hanging' the tiles externally.

The tiles are black salt-glazed tiles and appear to be machine made (they are all stamped) with some kind of trademark.

My apologies on the 'felt' reference...my roofers had actually suggested protec breathable membrane. Will take your advice and see what SPAB suggest.

 

[Penners]

Aaah - so we southerners have a wider vocabulary?

 

[Nemesis]

Nope - see link above!

The tiles sound interesting though - pics???

(My roofing slates are hung on laths.)

 

[Penners]

Here in East Anglia, black glazed pantiles - while not common - can still be seen from time to time. I quite like them, except (as in the case of a near neighbour) where one has been used in the midst of a red clay pantiled roof!

 

[Nemesis]

I have on occasion seen green glazed!

 

[GK]

Well - I thought laths and battens were one and same.

Laths that are spaced according to gauge and allow tiles to be hung from them are - laths. Or battens.

But-

whereas the laths are packed tightly against each other and therefore leave no means for 'hanging' the tiles externally

I'd call that solid sarking.

PS
When the laths are laid down the rafter, over the felt, they're counter-battens.

 

[Nemesis]

Thought that would bring you out of the woodwork! (ouch...)

 

[Penners]

Well - I thought laths and battens were one and same.

Do I detect this thread turning into a north-south semantic joust?!

 

[Sal]

And "old" doesn't always mean "high quality"! In any event, tiles are now slipping and the roof is leaking.

In my view there comes a time when pragmatism must apply, and this is one of those times. Above all else (metaphorically and actually!) a building needs a good roof. If I was going to spend time and money creating a home underneath that roof, I would want it properly felted and battened, as Middi said.

It's worth remembering that they had cowboys back then too....

I agree with Penners and Middi here

Sal

 

[Me!]

How steep or shallow is the pitch of the roof?
In the Charente region of France, the pitch of a roof is traditionally very low, and the tiles are not fixed on at all. Planks of wood are fixed between the rafters, and the tiles just rest on them. Look at the underside edge of the roof in this picture -
http://www.englishouse.de/html/english.html