Black timber cladding

[BartW]

Hi all,

 

We are installing open rain screen vertical cladding on our TF build, but my worry is that we will be able to see battens through the 10mm gaps.

 

How do people normally go about it?

- paint battens? crazy time consuming

 

- throw another layer of cheap breather? perhaps even geotextile? expensive given the m2

 

- not do anything?

 

 

[gc100]

We had planned on going this, you will need a UV stable  membrane behind.

 

we ended up not doing it after seeing a couple of places that had been done in the past. Just no garantee the membrane will last and then the critters will move into your structure. 
 

We went with a slotted profile in the end 

 

 

[BartW]

Thanks,

Our timber is on site, and arguably open rain screen would look better if spaced out as planned. 

I found some UV membranes, but they are stupidly expensive. I wonder if I should just paint the battens and be done with it that way...

[markocosic]

Paint.

 

It's what you have behind the rainscreen already UV proof?

 

If not think again...

[Kelvin]

Yes you will need to paint and protect it. As it happens I visited a rain screen timber clad building at the weekend and the battens weren’t painted and it was the first thing I noticed and very obvious. 

[Thorfun]

20 hours ago, BartW said:

I found some UV membranes, but they are stupidly expensive. I wonder if I should just paint the battens and be done with it that way...

as @markocosic alluded to, you need a UV membrane on the outside of the TF if you're having a shadow gap/rainscreen profile regardless of whether you paint the battens or not.

 

we have friends who had shadow gap cladding and mistakenly had a silver membrane on the outside of the TF. they put another black UV membrane on top of the battens but they checked with the manufacturer to ensure that it was ok to have the 2 membranes.

 

we chose neither paint nor a secondary membrane and had the tongue and groove shadow gap profile for our charred timber cladding.

[Russell griffiths]

If i was having an open gap, I would forget any membrane and clad the whole outside with a fibre cement sheet then paint the lot black, 

or even exterior ply with a black waterproof coating. 

I wouldn’t be happy with a membrane. 

[ToughButterCup]

7 minutes ago, Russell griffiths said:

If i was having an open gap, I would forget any membrane and clad the whole outside with a fibre cement sheet then paint the lot black, 

or even exterior ply with a black waterproof coating. 

I wouldn’t be happy with a membrane. 

 

Our membrane is part of our air-tightness strategy.  Yes it was expensive (£1000 for a 10 by 10 by 5 'block' of a house)

Yes,  wasps   chewed through the membrane - egg cup size hole: it was easy to see because of  the design gaps in the cladding

 

It was a 10 minute repair.

I'd like to have the time to do a cost comparison - labour and materials..... 

[BartW]

Ok, 

 

So certain thing highlighted itself:

 

Timber frame panels are factory wrapped in https://glidevaleprotect.com/product/protect-tf200-thermo-insulating-breather-membrane/ It is not UV resistant...

 

Given the above, is my only option to wrap another layer of black UV breather? Or could it be black NON-breather? and NON-UV? Black DPM?

 

Thinking about it, even if I paint all my battens, I will still see the reflective TF200 through the gaps, as that is silver colour.

 

Help!

 

 

 

[Tom]

As far as I understand it if you have gaps it needs to be UV stable, otherwise it will just break down over time. There seem to be different "grades" of UV resistance depending on how wide your gaps are - the wider the gap the more resistant it needs to be and the more expensive. Whether or not it needs be be able to breathe depends on the wall make-up I guess, but I think most (if not all?) UV resistant membranes are breathable

[Simplysimon]

go with board on board, no gaps, no issues.  

[BartW]

1 hour ago, Simplysimon said:

go with board on board, no gaps, no issues.  

You mean sit them tight? Not sure if I like it. Spent enough to make it special, taking away from that would feel wrong. 
 

[Simplysimon]

12 minutes ago, BartW said:

You mean sit them tight?

if you start with a 50mm wide board and overlap on top at each side by 20mm each side you will have a 10mm 'gap' between boards. what colour boards are you using? if plain timber then the 50mm backing board could be charred to show as black without maintenance costs, or, as @Russell griffithssays a black fibre cement board behind. you could use the 200mm cladding ripped into smaller strips to put behind the cladding. the cladding will be ventilated at the rear so it doesn't need to have the vertical gaps through to cavity.

[Thorfun]

26 minutes ago, BartW said:

You mean sit them tight? Not sure if I like it. Spent enough to make it special, taking away from that would feel wrong. 
 

Google board on board cladding to get an idea what it's all about. also there are threads on here on the subject as well. I think it looks good and you don't have to worry about crawlies getting behind your cladding.

[markocosic]

Subject close to my heart!

 

 

What you have won't work. UV will kill it. I'll dig out some local samples from the Baltic coast...

 

Insects will too in time IMO though this is debatated and depends on location and appetite of insects etc.

 

 

If you wanted to have open rainscreen cladding then you're going to need something insect and UV proof under it IMO.

 

 

You can't throw a non breathable membrane (e.g. EPDM) over the top of what you have without there being a ventilated rainscreen behind that non breathable membrane. 

 

When we looked at the UV proof and breathable membranes these cost a lot of limbs. They were the only option that let you "just throw a layer on" without materially changing the design though.

 

 

I'd also consider:

 

Shadow gap - though in pure black I don't think this is as effective as in lighter colours at creating shadows.

 

Board on board - create deeper shadow gaps by putting your boards on top of.some other boards such that the gaps are full depth (e.g. decking board type deep) but there's still closure behind them.

 

Board on tin - Use black wriggly tin / corrugated steel on top of your battens and fix through this into the battens. There world still be a ventilation gap behind this to let the house breathe...and it would look like there's nothing stuck immediately behind the boards...and it'd be black unlike your battens...and prevent insects uv and rain getting to your membrane. Gunned nails or self drilling wood screws will go through tin.

 

We ended up using board on board and shadow gap to get the look that she wanted:

 

[markocosic]

Local example of lighter but still dark shadow gap - I think shadows are stronger if you're using greys

 

[BartW]

Thanks chaps, I will do a full read at home, but the following look is what I am after.

 

What if I lay butting up?

 

[Thorfun]

22 minutes ago, BartW said:

What if I lay butting up?

afaik you need to have some kind of expansion gap so butting boards together probably isn't a good idea (although I'm no expert!). we had the same dilemma about painting battens and in the end chose the shadow gap route on both our charred and standard larch.

 

 

looks similar to those pictures you posted so I'm pretty sure they're not butted up but are a shadow gap profile.

 

if you've already got boards on-site then I think board on board might be your best option. unless you can take them to a timber yard and get them planned to a shadow gap profile?

 

 

[markocosic]

Those examples you show are almost certainly shadow gapped boards @BartW

 

Butted up soaking wet boards (in winter) will probably be 5mm mm gaps (uneven ones at that) in summer. Butted up in this weather will buckle and be a right state come winter. You need overlap and the option for the wood to move.

 

That black against plain larch looks sharp @Thorfun

[BartW]

The timber is now on site, and it would not be practical to rework it. It is charred all around, and there is over 300m2 of it.

 

I think I will carry on pursuing the open rain screen cladding, in which case I am assuming I need to go for:

- UV breather 

- insect mesh top and bottom, or just wrap breather tight to meet the wall and prevent any gaps top and bottom?

 

I think the above would be the most sensible solution, given where I lead myself to

Comments welcome!

[Thorfun]

8 hours ago, BartW said:

The timber is now on site, and it would not be practical to rework it. It is charred all around, and there is over 300m2 of it.

 

I think I will carry on pursuing the open rain screen cladding, in which case I am assuming I need to go for:

- UV breather 

- insect mesh top and bottom, or just wrap breather tight to meet the wall and prevent any gaps top and bottom?

 

I think the above would be the most sensible solution, given where I lead myself to

Comments welcome!

yeah, so if it's charred reworking the profile just isn't going to happen! if you still want the open rain screen then your assumptions are correct. check with the manufacturer of your chosen black UV breather to ensure that it will work in this situation though.

 

or, look in to @Russell griffiths previous suggestion as an alternative.

 

22 hours ago, Russell griffiths said:

If i was having an open gap, I would forget any membrane and clad the whole outside with a fibre cement sheet then paint the lot black, 

or even exterior ply with a black waterproof coating. 

I wouldn’t be happy with a membrane. 

 

[Russell griffiths]

You can get James hardie board in a 150mm wide plank you could put that in the gaps. 

However I would look at metal roofing supplies and buy a coil of flat black roofing sheet, probably on a roll cut to 150-200mm whatever and staple this in vertical strips behind where the gaps are. 

 

You can actually buy metal strips for creating a shadow a shadow gap between sheets of ply for use on decorative ceilings and stuff, but because England is stuck in 1860 I have only found it in America and Australia. 

 

@Patrick could probably help with the metal. 

[ToughButterCup]

19 hours ago, BartW said:

...

What if I lay butting up?

...

 

Ours (Siberian spruce) contracted (is still contracting?) a little. The original gap was 8mm: it is now 10 or more.

 

'Butting Up' I take to be laying the planks flush, side by side. If I'm right and your wood also shrinks then, over time,  I think a small gap will  open up. Thats the rationale for board on board cladding.

 

In relation to @Russell griffiths post above, here's a YT link to a superb Kiwi craftsman whose work I have come to admire: sometimes he uses shadow gaps in his ply - but inside. He 'makes' his own shadows like this .....

He calls it negative detail

 

 

 

[BartW]

Thanks guys,

 

cladding with cement board, or hardie, and so on sounds like another level of complicating it. Adds to fitting time / fiddliness, and costs as much as 25% to 30% of what I paid for the charred wood. 
 

I think good UV membrane is going to have to suffice on this one. Perhaps I will adjust my gaps to something like 5mm, so that come Winter cold, the gaps become wider. 
 

 

[saveasteading]

 

I have done many buildings with timber overclad,  all commercial or education but i think applies to domestic.

Usually we had a steel wall behind, fully sealed, but I think the same will apply for any modern construction.

Sometimes fully boarded, others with architectural gaps.

 

Timber will continue to shrink however well they say it has been dried.

Have always used battens so there is a gap behind.

Have never known of any problems with insects/ uv.

Of course any black membrane provided for appearance should breathe if that is the property of what it is covering. But this could be any cheap membrane as long as UV resistant.

Then stain, not paint, the battens to resemble the cladding.

 

Small gaps should be avoided.  A 5mm gap could expand to 10 or stay the same, and so the gap difference would be very obvious. Twisting of the wood wold have the same problem.

 

The only problems we have had were of excessive shrinkage, opening up gaps when there should have been none.