Nick1c

Experiences with larch and cedar cladding

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In an effort to alleviate my frustration at the glacial progress of our build I have (prematurely) started looking at the cladding options for it - there will be some vertical and some horizontal areas. 

The house overlooks the sea near lands end and will get a fair beating from the weather. It will have a slate roof (with some in-roof Pv), a small amount of white render and RAL7016 windows, we plan to let the timber grey. 

There appears to be a wide variety of opinions about the pros & cons of various options, I have listed what I have been told/ heard below and would be grateful for any information about people's real life experiences with them. The total cost is a combination of material price, labour & longevity and, as ever, there doesn't seem to be a simple answer. 

 

WRC: reassuringly expensive, the most stable (can be t&g), easily fixed (secret or face), no pre drilling, the most durable (30+ years) lightweight, prone to bruising, initial colour very variable, weathering can be uneven depending on exposure. 

 

Siberian Larch: half the price, moves a lot so best as half-lap (although can be bought as t&g), may need pre-drilling, less durable (15+ years), initial colour pretty even, heavier (2x the weight), hard wearing, weathering as above with the added possibility of blackening in damper/ sheltered bits. 

 

Silvalbp: SiLa with a sacrificial coating to give an instant 'final finish' look. 

 

Starting with the most basic question: is all wood of the same type (from places such as Russwood, Vincent, Mill Works, Vasterns) equivalent and is choosing the grade purely a financial/ aesthetic decision ( like oak flooring for eg.) or are there performance/longevity differences? Is kiln dried a good idea?

 

Has as anyone had any issues with fixing (splitting &/or movement), have people chosen to pre-drill for fixing, if joining pieces together have butt or mitred joints been used?

 

Are people who have used the age accelerators happy with them? Are they all equivalent?

 

Does using non-marine grade ss fixings in exposed locations result in staining (bad), or just a dulling/ tea staining of the visible part (potentially good)?

 

Any real life information on longevity of untreated timber in exposed locations. 

 

Anything else I have forgotten?

 

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I have Silvalbp Siberian Larch with new Age Gris sacrificial coating - via Vincent Timber.  Its a horizontal secret fix.  Stainless steel fixings used. The quality of the larch was far superior to other larch samples I had from Vastern etc

 

I had always thought I would have WRC and had lots of samples, was pretty set on one from Russwood with Siou coating.  Last minute unexpected swerve to larch when I saw the Silva lbp Larch sample  - it was a coup de foudre!

 

Reason for me dithering on the cedar was really because of the colour variations even from v expensive supplier - Russwood. I was also concerned with what you term bruising...if someone bashed a garden chair into it would not look good all dented. The larch is reassuringly heavy and feels more durable.

 

We are high on a ridge very exposed.  Our larch does not appear to have moved much on the house in the last year however my bin store and meter cupboards have had had a lot of swelling and shrinkage.  That may have happened on the house but we are just not aware of it.  I had a superb carpenter to fit it. Very experienced and took account of timber movement.

 

I wanted the sacrificial coating as I hate the uneven old shed look and blackened bits a no no for me.  Ours is crisp and beautiful and we have white render and RAL 706 too. I hope it remains as beautiful as it ages.

 

I can't say anything about the longevity as too new but I would be expecting more than 15 years from it.  The pic is last year about this time.

 

 

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I've only done horizontal oak cladding. Drilling was essential for that. Main issue is at the ends of planks. Lets say you have a joint between two planks. This is usually arranged to occur over a batten. If the batten is 2" wide each plank only has 1" over the batten. So you are nailing within 1" and possible less from the end of the plank. This makes it prone to splitting unless you pre-drill. Even then I drilled as far as possible from the end and at an angle into the batten. Use wide battens. Oaks also shrinks in length and having oversize hole helps stop the oak pulling the nails.

 

Think about nail heads. You will most likely be using Stainless Steel or some other metal that doesn't corrode in a salty atmosphere. Some types are available with textured heads so that they don't reflect the sunlight quite as badly. Some timbers like oak also corrode nails if made from the wrong metal so check that.

 

Unlike roof tiles oak planks aren't overlapped enough to prevent water going through joints between adjacent planks. So behind all butt joints I first nailed a 6" wide strip of DPM to the batten at the top and let the bottom end come out between the layers of planks. That way any water getting through a butt joint would be directed to the outside. Later trimmed off the exposed ends so you cant see the strips unless you look through a gap. 

 

 

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If you go for T&G check if you should/shouldn't fully seat the T into the G. I had some doors made that used T&G. The folks that made it fully seated the boards so when the wood expanded the whole door bowed and looked pregnant. If they hadn't fully seated the T&G there wouldn't have been a problem.I'm not sure if the same applies to T&G cladding but I don't see why the same problem couldn't arise? Perhaps it depends on time of year/humidity levels when installed?

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45 minutes ago, Temp said:

I've only done horizontal oak cladding. Drilling was essential for that. Main issue is at the ends of planks. Lets say you have a joint between two planks. This is usually arranged to occur over a batten. If the batten is 2" wide each plank only has 1" over the batten. So you are nailing within 1" and possible less from the end of the plank. This makes it prone to splitting unless you pre-drill. Even then I drilled as far as possible from the end and at an angle into the batten. Use wide battens. Oaks also shrinks in length and having oversize hole helps stop the oak pulling the nails.

 

Think about nail heads. You will most likely be using Stainless Steel or some other metal that doesn't corrode in a salty atmosphere. Some types are available with textured heads so that they don't reflect the sunlight quite as badly. Some timbers like oak also corrode nails if made from the wrong metal so check that.

 

Unlike roof tiles oak planks aren't overlapped enough to prevent water going through joints between adjacent planks. So behind all butt joints I first nailed a 6" wide strip of DPM to the batten at the top and let the bottom end come out between the layers of planks. That way any water getting through a butt joint would be directed to the outside. Later trimmed off the exposed ends so you cant see the strips unless you look through a gap. 

 

 

The advised practice is to double up on the vertical batten where the joint meets to keep the fixing away fro the end of the board. There are lots of examples of details for fixing cladding from the likes or TRADA. Use a well ventilated cavity behind the cladding, normally ventilated top and bottom with an insect mesh to keep the critters out. Definately stainless steel ringshank nails. WRC is very soft and a nail gun is likely to make a right mess. You can nail gun larch but best results are from an air powered gun with nails on a roll so they have round heads not crescent.

What is really important with any timber cladding is how it is detailed around openings. Dont just rely on your chippie to do what he wants. Get hold of some proper details and agree them before it starts to go up and get flashings made for window heads, cills etc. These will effect the depth the windows are fitted in to the openings.

Edited by Alex C

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39 minutes ago, Alex C said:

WRC is very soft and a nail gun is likely to make a right mess. You can nail gun larch but best results are from an air powered gun with nails on a roll so they have round heads not crescent.

 

If you buy a "no mar" tip for your Paslode 1st fix nailer and make sure you carefully adjust the embedment depth, you should be OK, but hand nailing is safest.

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47 minutes ago, Mr Punter said:

 

If you buy a "no mar" tip for your Paslode 1st fix nailer and make sure you carefully adjust the embedment depth, you should be OK, but hand nailing is safest.

I can't believe you get anything other than a dodgy job using a first fix pasload on WRC, maybe with a thick board but not nailing feather edge. Can you get a round head on a Padsload as the clipped nail heads look terrible. 

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All the timber you are buying is pretty much dependant on where it comes from. In general all the Larch grown in the UK is of fairly low quality. Makes sure you are buying Siberia  Larch or European Larch from somewhere like Poland, Czech, Austria, where there is a proper winter and some mountains. This makes the larch grow slower and the wood of a better quality (harder wood).  I don't know if this is something that regularly happens, but I was advised by UK timber dealer and sawmill to hang Cladding wet. This is complete rubbish  and should be avoided at all costs. Only a sales tactic to get rid of wet timber and never heard this anywhere else. So either air dried or kiln dried. When properly dried shrinkage and movement with Siberian larch should be minimal, specially if you keep the timber on site for a few weeks before installing to let it "adjust" to local conditions. Also normally you should get way more than 15 years out of a decent batch of larch board.

IMHO the most solid form of cladding is Board on board or board  and batten (also Wayne Edge does something similar) as it allows the timber to move. Does not matter which one you use, all timber will move at least a little so I would prevent faults by using a technique that has been proofen for a few hundred years.

Value/money siberian larch is pretty unbeatable.

The high Sap content is making it so durable and it is still easy to work with. Instead of pre drilling, I would hand nail it.

Edited by Patrick
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11 minutes ago, Patrick said:

All the timber you are buying is pretty much dependant on where it comes from. In general all the Larch grown in the UK is of fairly low quality. Makes sure you are buying Siberia  Larch or European Larch from somewhere like Poland, Czech, Austria, where there is a proper winter and some mountains. This makes the larch grow slower and the wood of a better quality (harder wood).  I don't know if this is something that regularly happens, but I was advised by UK timber dealer and sawmill to hang Cladding wet. This is complete rubbish  and should be avoided at all costs. Only a sales tactic to get rid of wet timber and never heard this anywhere else. So either air dried or kiln dried. When properly dried shrinkage and movement with Siberian larch should be minimal, specially if you keep the timber on site for a few weeks before installing to let it "adjust" to local conditions. Also normally you should get way more than 15 years out of a decent batch of larch board.

IMHO the most solid form of cladding is Board on board or board  and batten (also Wayne Edge does something similar) as it allows the timber to move. Does not matter which one you use, all timber will move at least a little so I would prevent faults by using a technique that has been proofen for a few hundred years.

Value/money siberian larch is pretty unbeatable.

The high Sap content is making it so durable and it is still easy to work with. Instead of pre drilling, I would hand nail it.

Mine was all hand nailed.

 

The silvalbp larch is grown in the Alps .....Annecy area. Its factory coated and dried and comes wrapped in plastic. They are a french company.

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9 minutes ago, Patrick said:

@lizzieThan it's decent stuff. Probably not cheap but looks good.

Yes not cheap but its lovely worth every penny

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I'm currently cladding with Siberian Larch (well, when if stops effing raining..).  It's rebated feather edge.  My battens are as shallow as I thought could get away with (25mm) because I don't want to loose any more of the plinth bricks than I have to, hence batons at 400~450mm spacing, and all screwed with stainless steel cladding screws. I've left  ~ 3mm expansion gaps between boards, and I dont expect to see much movement on it; it feels solid. Holes at the ends of boards are pre-drilled for good measure, and yes, it is taking forever!  I've bought Sioo:X to treat it, but it will be a few more weekends before I get that on.  This is my first/practice end:

 

edited.thumb.jpg.8047907f2d15676a43499af7fb1c2d32.jpg

 

 

 

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9 minutes ago, Roundtuit said:

I'm currently cladding with Siberian Larch (well, when if stops effing raining..).  It's rebated feather edge.  My battens are as shallow as I thought could get away with (25mm) because I don't want to loose any more of the plinth bricks than I have to, hence batons at 400~450mm spacing, and all screwed with stainless steel cladding screws. I've left  ~ 3mm expansion gaps between boards, and I dont expect to see much movement on it; it feels solid. Holes at the ends of boards are pre-drilled for good measure, and yes, it is taking forever!  I've bought Sioo:X to treat it, but it will be a few more weekends before I get that on.  This is my first/practice end:

 

edited.thumb.jpg.8047907f2d15676a43499af7fb1c2d32.jpg

 

 

 

If you still have some to do I would get the Sioo x on it before you put it up, much easier to do it on trestles

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1 hour ago, lizzie said:

If you still have some to do I would get the Sioo x on it before you put it up, much easier to do it on trestles

 

Thanks for the tip.  I was planning to get it up and let it dry/shrink for a week or two (weather permitting..), then spray the treatment on with a 2l pressure sprayer.  I might try both.

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The difficulties of sealing joints in horizontal cladding must be one of the reasons that more exposed properties tend to use vertical boards.

Up here on Skye it is predominantly board-on-board vertical larch, which is what I went with. This is, I think, the best choice for an exposed location.

 

I was in a different price bracket to the OP and sourced locally grown larch which is not of the best quality, but was extremely good value for money (under £10/m2 including overlaps). It is rough sawn finish and there is some sap wood, but I was able to hide the worst of it and use the best boards in the most aesthetically important areas.

 

For fixing, a coil nailer is fantastic. The (stainless) nails are full head, so they look right. You can fit hundreds of nails in a coil, and they're cheaper than stick nails. 

I did pre-drill and hand-nail if the fixing was within a couple of inches of the end of a board, as otherwise there was a risk of splitting.

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8 minutes ago, Tin Soldier said:

lizzie, what have you got above your window reveals? slate? metal?

pc ali header strip we had fabricated to match windows

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16 hours ago, Crofter said:

The difficulties of sealing joints in horizontal cladding must be one of the reasons that more exposed properties tend to use vertical boards.

Up here on Skye it is predominantly board-on-board vertical larch, which is what I went with. This is, I think, the best choice for an exposed location.

 

 

Vertical boards definitely work much better in scotland (especially west coast) if you use horizontal, the joints always open up due to the extremes of wet and dry, then you get saggy boards. Board on board is a more traditional (in scotland) way to clad because the quality of timber is less important and it will weather better, have had to work hard to convince some clients not to put on the cheapest pine weatherboard a few times!

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