'Lead alternative' flashing

[JohnW2]

There are currently five "similar threads" showing at the end of this thread, they all look helpful

Yes, as I implied in my initial post, I've seen them, and also a few other threads found by searching the forum.

However, as I also implied, none of those previous threads really addressed the primary question I was asking - regarding how Flashband etc. differs (thickness, materials, construction, performance) from Ubiflex/Leadax etc.

Kind Regards, John

 

[JohnW2]

I've just been doing some very rough price comparisons, which (as expected) show very substantial differences.

On the basis of the nearest available roll sizes on offer, I've roughly estimated (pro-rata to area) the approximate average cost of a 225mm x 10m roll, as follows:

Flashband and similar - £23
Ubiflex - £97
L:eadax -£104
Code 4 Lead - £210

Particularly given the current financial climate, find it hard to ignore these differences!

Should I decide to go with the 'middle' option, does anyone have any preferences as regards Ubiflex and Leadax (or any other similar)?

Kind Regards, John

 

[datarebal]

ubiflex or wakaflex id say if you cant run to the proper product

 

[JohnW2]

ubiflex or wakaflex id say if you cant run to the proper product

Thanks for your input. It's not really a matter of 'what I can run to' but, rather, what is sensible in my situation.

It's not so much the difference between Ubiflex etc. and 'the proper product' (lead), since that is 'only' roughly a 2:1 price difference, but more the fact that the cheapest approach is seemingly nearly 5 times cheaper than Ubiflex and nearly 10 times cheaper than lead.

In these situations, it's only too easy to give the 'optimal'/'official line' answers/advice (and I knew what that would be, anyway). What I still am not really clear about is, if I were to go with 'the cheapest option', what would be likely to go wrong, and how quickly - remembering that I am not looking for 'many years' (let alone decades) of service.

Kind Regards, John

 

[robinbanks]

would there be any appreciable advantage in using an alternative' rather than lead itself (if I wanted to spend that much)?

The alternatives are sometimes easier to work with because they're lighter, and [for Leadax, maybe others] you can use an entire roll length of 6m in one run whereas there are limits for lead in terms of limiting problems caused by thermal expansion.

Lead also needs treating (ideally both sides, but on the underside you might be able to get away with just treating visible parts eg through a glass roof, or parts exposed to wind driven rainwater) during/after install to prevent powdery white lead carbonate forming in contact with water. Lead carbonate is water soluble and in time dissolves off the lead, washing down the roof/roof lights leaving a stain. It's a pain in the ass but can be removed, though definitely easier to avoid in the first place.

Another advantage of alternatives is that lead is generally quite toxic in any of its forms, and any reasonable opportunity not to put more of it into the environment should be considered

 

[datarebal]

In these situations, it's only too easy to give the 'optimal'/'official line' answers/advice (and I knew what that would be, anyway). What I still am not really clear about is, if I were to go with 'the cheapest option', what would be likely to go wrong, and how quickly - remembering that I am not looking for 'many years' (let alone decades) of service.

use gaffa tape then even cheaper

 

[JohnW2]

use gaffa tape then even cheaper

True, but I don't want/need to go quite that far. and I suspect that might not last very long at all

Kind Regards, John

 

[JohnW2]

Not sure that the aluminium layer in flashband would take kindly to being mortared over, and that's the layer that would give the UV resistance to stop the sun destroying the rest of it

I questioned you about that, and have now looked at the Flashband documentation, which says:

Bostik Flashband Self Adhesive Flashing Tape for Roofs may become brittle if enclosed in a cementitious mix. Contact between the foil and acidic or alkaline materials must also be avoided. Avoid using Bostik Flashband Self Adhesive Flashing Tape for Roofs where it will come into regular contact with solvents and oils. Bostik Flashband Self Adhesive Flashing Tape for Roofs is bituminous and must not come into contact with silicone sealants, flexible PVC or vinyl

... which seems to imply that one shouldn't 'seal' it into chases with mortar and is also restrictive in other ways.

It also says:

15. Fully bonded Bostik Flashband Self Adhesive Flashing Tape for Roofs will not accommodate appreciable joint movement.
16. For small movements apply a strip of release backing, 50mm narrower than the Bostik Flashband Self Adhesive Flashing Tape for Roofs, along the joint prior to the application of the Bostik Flashband Self Adhesive Flashing Tape for Roofs.
17. For larger movement, polyethylene foam can be laid proud of the joint, so enabling the web of supported Bostik Flashband Self Adhesive Flashing Tape for Roofs to accept the movement.

Is this referring to 'joints' between lengths of Flashband?

Kind Regards, John

 

[JohnW2]

The alternatives are sometimes easier to work with because they're lighter, and [for Leadax you can use an entire roll length of 6m in one run whereas there are limits for lead in terms of limiting problems caused by thermal expansion. .... Lead also needs treating (ideally both side ....

Thanks for explaining.

Another advantage of alternatives are that lead is generally quite toxic in any of its forms, and any reasonable opportunity not to put more of it into the environment should be considered

Yes, that is a consideration - as, of course, is that of potential theft.

Kind Regards, John

 

[Harry Bloomfield]

True, but I don't want/need to go quite that far. and I suspect that might not last very long at all

Kind Regards, John

Right or wrong, as an extra seal, I used cheap Flashband around my chimney 20 years ago - it didn't solve the problem, but the point is it has survived just fine over the years, in a very exposed location. It was stuck a couple of brick courses above the lead, covering both bricks and partially the lead.

The problem was there was a very slight amount of damp ingress appearing down the sides of the chimney, but only in the loft. Some years ago, I had the flaunching on top of the chimney redone, which seems to have resolved the problem.

 

[Harry Bloomfield]

Is this referring to 'joints' between lengths of Flashband?

No, I would suggest it means movement between the surfaces it is in contact with, what it is stuck to. Continual movement, expansion and contraction, in a short area of the Flashband, will cause it to rip.

 

[JohnW2]

Right or wrong, as an extra seal, I used cheap Flashband around my chimney 20 years ago - it didn't solve the problem, but the point is it has survived just fine over the years, in a very exposed location. It was stuck a couple of brick courses above the lead, covering both bricks and partially the lead.

That's rather what I suspected might be the case. Did you 'chase it in' (and, if so, did you use mortar or sealant), or was it just 'stuck on'?

I don't think I'll use lead. However, given that I really would be happy with, say, 5-10 years 'life', if not more, I'm oscillating fairly violently between Flashband (etc.) and the "5 times more expensive" lead alternatives. It's a bit like so many of the issue we discuss in the Electrics forum - there is usually a 'proper' solution (e.g. replace an entire damaged/cut cable) but also often a simpler/cheaper/more convenient alternative (e.g. repair cable 'with joins') that is usually perfectly fit for the particular purpose!

Kind Regards, John

 

[JohnW2]

No, I would suggest it means movement between the surfaces it is in contact with, what it is stuck to. Continual movement, expansion and contraction, in a short area of the Flashband, will cause it to rip.

That was the other possible interpretation I considered, but given that it would most commonly be stuck to brickwork, concrete, felt or whatever, I wondered exactly what sort of 'joints' they had in mind.

Kind Regards, John

 

[Harry Bloomfield]

That's rather what I suspected might be the case. Did you 'chase it in' (and, if so, did you use mortar or sealant), or was it just 'stuck on'?

It was just stuck in place, then I think a small roller was run over it, to improve the stick.

 

[Harry Bloomfield]

That was the other possible interpretation I considered, but given that it would most commonly be stuck to brickwork, concrete, felt or whatever,

I also remembered using some on nailed down felt - where there were joints, and possible movement, the Flashband split due to the movement.