Finial tannins meets lime wash

[leucothea]

What to do!

The root cause here is the slope of the wall. But the finial is new and I guess full of tannins. The rain was also especially heavy yesterday.

This whole gable is shortly going to become inaccessible and I can only think of crude options like attaching a bit of lead underneath and behind the finial to act as a kind of temporary gutter until the tannins are reduced.

I guess I'm also concerned about dampness on that lower corner of the window (which is accoya painted with something breathable) from water running down the finial over time.

Any thoughts would be appreciated!

 

[Cubist]

I am not convinced the staining is caused by the woods tannins and suspect it may be oil, or similar in which the finial timber was soaked to preserve it.

This is going to sound a little silly but... you could fashion a length of sheet polythene into a tube that is long enough to reach from the ball of the finial down to the exposed rafters below and tie off each end. Any run-off from the finial, along with the tannins/oils, will be carried down to spill safely onto the roof below with minimal spillage onto the lime render.

The biggest challenge though may be covering the existing stains in the render. These may resist any final coating you might wish to apply and thus force you to remove that section of the render.

 

[a twig]

If you want to do Cubist’s ideas with less furling of plastic sheet, temporary downpipes are also available like this:

20 Metre Rainwater Long Temporary Downpipe with 8 Cable Ties for Gutter Outlets and Storm Drainage | DIY at B&Q

Ensure optimal water management and protection for your construction projects with our high-quality temporary downpipe. Crafted from heavy-duty polythene, this downpipe connector is designed to withstand the harshest weather conditions, providing reliable performance for both short-term and...

www.diy.com

 

[Kearn]

it is tannin from the wood. Sadly it may do it for some time. The front elevation of our house rarely gets hit by weather, but the scaff has changed that and directed water into the elevation and 500+ year timbers are still giving up some staining… bizarre.

The rear elevation which is almost all new 3+ year air dried oak, is staining panels like crazy right now. Not much that can be done here until it doesn’t stain anymore. Then the panels will need redoing if I want to lose the marks. In the next five or so years we’ll have to revisit the panels anyway to deal with the shrinkage gaps once the timber has dried out.

Pretty sure there’s nothing that’s going to mask it.

I’m not sure how helpful it is, but you do still have scaff up so some choices…. I’ve oversailed our tiles and barge boards significantly on the weathered gable so they are very proud of the face.

It may be that the finial needs to be dealt with as it will always drip there. Even if you fashioned one from an ancient piece of timber which (hopefully) didn’t stain. How far out can you project it so it drips past the building?

Alternatively a pentice hood over the window to deflect the drips.

 

[leucothea]

Thank you for the advice.

I’ve gone ahead and done what I can in the limited time available, which is to install a swift box with a lead roof underneath the finial to act as a kind of gutter. Seems to work fine.

The swift box is made of a cement-wood mix and took lime wash reasonably well, and so matches the wall.