Rotten felt - 4 different diagnosis - how to decide what to go with?

In my opinion if is getting through tiles which they are probably old barns thay all to come off shut the gauge done to compensate for shoulder tiles then look at recent and bsttern

under felting is a secondary barrier for water ingress. so if water is getting in then its coming in from either the tiles or the lead flashing condensation highly unlikely if its only leaking when its windy and rain so eliminate that one plus you would have to add more than one tile vent to ventilate a loft space this will also not create a cross vent flow unless u have ventilated eaves or soffits replacing the felt at eaves level will only guide the water out to the guttering not solve the actual issue as that will leave water still getting through the tiles or lead flashing the lead flashing being to short could be a possibility and is common could also be lead flashing split / cracked due to its age if two roofers have said the same it is most possible the cause but as a belt and braces id also seal the brick work the lead flashing goes into as old brickwork can become porous and suck up water like a sponge and that will end up below if there are no cavity trays or damp course hope this helps

If they are old clay pan tiles then water could be getting in the gaps where mitred on top right corner as previously stated ideally need re gauging. Secondly if the water is going through the tiles, Yr felt should be also providing protection and is clearly failing. So I would suggest removing the first 5 to 6 rows of tiles remove 1st row (eaves) of existing felt and battern, Install eaves / felt support trays then install a new row of membrane/felt and battern to the correct gauge, finally reinstall tiles.

Hi, If you are getting water in your roof and it’s an old roof,in my opinion it’s just the beginning of many problems. If you can afford it and get help from your home insurance ,wait till a decent dry patch comes then strip the roof and put the good tiles to one side. Inspect your rafters because if you have water damage they can fail ,all you need to do is bolt new ones to them and make sure they are connected to the ridge beam and wall plate securely. At this point you can add insulation if you don’t have it the government will help maybe through the green deal ,it is imperative that you leave 50mm air gap at top edge of rafter and install vented soffit for good airflow. Then put an eaves felt support tray all along the bottom edge of rafters ,then use a premium breathable felt like klober etc on top of your tray and continue up to ridge. Tile and battern as normal remembering to use an additional eaves course and mix in randomly some new tiles with the old ones. To finish of use a dry vent ridge kit to ensure the air flows from soffit to ridge above your insulation in the 50mm air gap . Lots of different builders with lots of different ways to build but this is the premium way that will work and leave you warm,dry and content. If you start patching and making good now it will never end because the water could be coming in from many places good luck.

First, the water should not be getting through the tiles at all. If it is getting through at eaves level, it is likely that one of the tiles at eaves level is broken. At eaves level there is a short tile and the next tile covers it so you might not be able to see that one of the tiles in the first row is broken. In order to ascertain whether this is the case, strip back the tiles in this area and you will then be able to see the felt and battens, as well as the first row of tiles. An eaves tray is a good idea as this provides extra protection at this level which is vital as this carries the most rainwater in heavy rain. The eaves tray should be positioned so that it takes water directly into the guttering. Over this, hang the first coarse of short tiles. The next row should finish flush with the first row. After that, the tiles are hung overlapping the row below sufficient for the pitch of the roof and the weather conditions (a bigger overlap is needed in very exposed locations). Tiles can be nailed down rather than just hung on their nibs in order to stop them lifting. Sometimes this is done very third row. They should be easy to lift and then you will have a better idea of how to proceed. Thanks, Tom's Team Ltd.