FLUE INSTALLATION THROUGH SLATE ROOF

[DAV1D]

HI CHAPS

Last week I visited a terraced house which I went to to give a quote on
installing a complete central heating system.
Where the owner wishes the boiler to be installed requires the flue to extend through the the slate tile roofing.

Having not carried out this particular job before, is there an easy method of cutting the the required diameter hole,(obviously this will be elliptical)
thus ensuring that the flue sealing plate will provide a water tight seal. Will a require any special tooling i.e slate ripper etc?
Do you necessarily need to strip out numerous tiles to satisfactorily complete the job in question, if so what would the correct procedure be?

Also could you inform me how access to the work area may be safetly accessed with a roof type ladder i.e. How ladders may be secured to ensure no nasty accidents?


Best
Regards
dav1d

 

[ChrisR]

I assume you're corgi reg'd - if not don't be stupid, you won't have a clue what you're doing.

Otherwise - First get the fitting which will either be (best) a boiler mfrs part if going vertically through the roof, or possibly a general "lead slate" (Made of rubber and aluminium!) if going horizontally. Then you'll be a lot more confident about the lack of need for accuracy in making the required hole.

Horizontal is often easier, and though rarely covered in the manual, the corgi inspectors seem to approve.

Then get the important ingredient - a roofer. It's much easier with two people anyway, especially where say part has to be lowered through a roof and you inside have to cut to length.

 

[DAV1D]

hi Chris
Thanks for your reply and by the way I'm sorry I forgot to mention I was Corgi registered.
I tried posting this message in the roofing section but had no response so I though I would try this the plumbing section.
I've been through a career change the last two years,previously a mechanical engineer, and have installed a number of combi boilers all of which were flued though an outside wall.
I just wanted some guidance on how I could tackle the problem.
Would you do this yourself for example , where or will you draw the line if the roof heigh or inclination is unacceptable to work off a roof ladder ect .
Would you suggest that this work is subcontracted and added to the quote
How much would I expect to pay for this assistance


Thanks again for the reply
Dav1d

 

[DP]

Source a vertical flue kit for the boiler in question. It will come with all the bits and pieces.

Correct way to go for it is to get a roofer to do the roof side of the work. Drop a plumb from the exit point such that it finds the centre of the flue port on the boiler. Make a hole in the sarking and let the roofer strip the immediate area around the exit point of the hole. Cut a hole in the sarking with specified air gap between combustible sarking and flue. You may need to have exterior grade ply to hand if sarking is weakened by the hole (which will be approximately 200mm in dia- if I remember correctly). Offer the vertical kit through the flashing that the roofer will have installed onto the hole. You control the positioning of the flashing. He passes the flue through the flashing to you having located the weathering collar onto the flashing. Fit extension pieces as needed between the roof section and boiler. Install flue brackets to secure the flue.

Roofer to replace slates as needed.

 

[DAV1D]

HI dp
Please could you tell me what a sarking is I am not familiar with this term sorry
Regards
Dav1d

 

[peter anderson]

The flue will have to have a lead flashing over it to stop rain from going between the flue and the tile. This is a skilled job which you may have to subcontract out

 

[ChrisR]

David. I'm another career changer so I know where you're coming from. We didn't do apprenticeships like we should have done so we don't get taught this stuff by experienced blokes!

The horizontal route is only OK if you can go straight off the top of the boiler sideways. Seems to happen thet way for me quite often though.

Sarking is the thin felt stuff which is often just under the tiles/slates.

You don't need a real lead flashing + tube thing they used to call a "lead slate" , you buy a modern equivalent. As DP says the boiler mfrs bits will include one, though there are lots of proprietary ones around, eg made by "Ubink" which are a thick but flexible metal plate with a centrl rubber collar which squeezes against a flue or soil pipe. Ask in your merchant.

I certainly wouldn't go on a roof more than ground floor height. The roofers I use to help with this sort of caper are very helpful, but it's very quick job if YOU have done all the work you can on the inside. Cut out the felt and tile support laths which have to go. I show them from the outside, go inside and poke the tiles where I want the hole and they go up top and remove them, lower the mfrs flue bit through and I just have to cut it to length. I mean they're very helpful - they dance about the roof replacing cracked tiles with the ones they've just removed, while I'm sawing the flue off. So you can charge the customer a bit for that if you want.

I give them notice of several days, find a slot when they can call by and they charge about £60 - for 20 mins work for them, which is fine by me!
I'm sw london /surrey by the way.
I need hardly add that I agree with everything DP says!