The short answer
Not in any way that lasts. Roofing felt, or underlay, lies under the battens that hold the tiles, so renewing it means lifting the covering. A few repairs reach a torn patch from the loft side, but a proper re-felt strips the slope, lays a new membrane, fits new battens and puts the tiles back or replaces them.
Why the tiles have to come off
On a pitched roof the layers run in a fixed order. The rafters come first, then the underlay laid across them, then the battens, the thin timber strips nailed on top, and then the tiles or slates hooked or nailed to the battens. The felt is trapped beneath the battens, so it cannot be slid out like a drawer.
Underlay is the back-up layer beneath the covering. Tiles turn away the bulk of the rain, yet gusts can push water up beneath them, and the membrane catches that and sends it toward the gutter. When it is old, brittle or torn, damp can reach the timber even though the tiles look perfect from the garden.
You may hear of a repair done from the loft side, with a patch stuck over a visible tear. That can buy time on a small section, but it remains a temporary patch rather than a re-felt. A felt that has failed in one place has usually aged everywhere, because the sun, heat and age that wore out the first patch have been at work on all of it.
A real replacement means stripping the slope in stages, with a temporary cover on at the end of each day.
How Windsor and Maidenhead treats re-felting
Replacing felt is not only a weatherproofing question. When the covering is lifted and the layers are renewed, building control can have an interest. The Royal Borough of Windsor and Maidenhead (RBWM) gives re-felting as one example under its thermal elements heading, work it treats as renovation, the walls, floors and roofs that keep heat in.
That wording belongs to RBWM and its own addresses. The national position is in the Building Regulations 2010, where renovation of a thermal element includes adding a new layer or swapping a layer that is already there. Approved Document L adds that a renovated roof worse than a threshold U-value should usually be upgraded, the U-value being the measure of how much heat passes through it, which can mean adding insulation when the roof is open.
For Rushmoor addresses, the Planning Portal test of less than 25 per cent of the building envelope and less than 50 per cent of the roof is the guide. Bracknell Forest and Basingstoke and Deane list replacing roof coverings among works that may need approval. We check the council's own page for your address before the strip, and the page on insulation when re-roofing explains the energy side.
Breathable membranes and ventilation
Underlay comes in two kinds, and they behave differently. High-resistance (HR) underlay does not breathe, so moisture cannot pass it and the roof space below needs ventilation at the eaves. Marley gives the BS 5250 figures for a cold roof with this type: 25mm of ventilation along the eaves for pitches of 15 degrees or less, and 10mm for steeper pitches.
A low-resistance (LR) underlay is a breathable membrane. It lets water vapour from the house escape through the membrane, so a tight ceiling and ordinary eaves construction can do the work of ventilation. Marley sets a condition on that: the product needs third-party certification for the use. BS 5250:2021, the code of practice on moisture in buildings, is current and under review.
The right choice follows from how your own loft is built. A membrane laid without thinking about the ventilation path can leave condensation in the loft, and the damp is then blamed on a leak. Approved Document C wants roofs to resist rain and to avoid condensation that harms the structure itself.
We name the membrane type in the written scope after the survey, along with the eaves detail it relies on, so you can see what is going above your head.
What a re-felt costs you in time and tidiness
A re-felt is a strip job, and it follows the same stages as a re-roof. Scaffold goes up first so the roofer can work safely at the eaves. The tiles come off in sections, sound ones are stacked for reuse, and the old felt and battens go into a skip. The new underlay is laid from the eaves upward with correct overlaps, new battens are fixed, and the tiles go back.
Because the covering is lifted anyway, it is the right moment to look at the timbers, the lead flashings and the ridge. Our page on replacing roof timbers covers what a strip can uncover, and reusing old roof tiles explains which tiles go back.
On the survey we photograph the loft side of the felt, note the membrane type and measure the slopes, so the written price is for a known job. You see the evidence first. If a patch repair will really do for a short while, that is what you will be told, since the smallest sound fix is the right one. Our roof replacement page sets out the whole sequence.
