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Sealing and waterproofing knots

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Sealing and waterproofing knots

Postby smojo » Wed Oct 08, 2014 7:37 am

I bought a logstore for my back garden. Tannalised something or other. Looks nice and well made but it has lots of knots in the roof laths and when it rained the other day, lots of dripping leaks through them. I don't want to cover the roof with ugly felt but I do want my logs dry (not unreasonable). I think two things are happening, the knots have dried out and got thin cracks running through and around them but also the direction of the grain being at right angles to the laths is acting as a channel, so if I can seal them, it should stop water getting through. I want to keep the colour of the wood more or less natural so no bitumen products to be used. So my plan is to somehow seal the knots first with something liquid and durable (preferably clear or amber coloured) then give the whole roof a few coats of yacht varnish or something waterproof. Can anyone suggest a good product to seal the knots first and is there a better product for the rest of the roof.
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Re: Sealing and waterproofing knots

Postby Wendelspanswick » Wed Oct 08, 2014 8:20 am

I think you are on a hiding to nothing trying to seal the roof that way. The problem is that the timber is always moving, shrinking in dry weather and expanding when wet. You might succeed in sealing it now but new cracks will open up next time.
Can you take the roof off, put in a sheet of roofing membrane or felt and then put the roof back on?
That way any rain that finds its way in will run down the membrane and back out.
That's the method I used on my treebog.
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Re: Sealing and waterproofing knots

Postby smojo » Wed Oct 08, 2014 8:53 am

Yes the roof will come off. I have thought about that method too but wondered if it would trap moisture between roof and membrane and cause it to go mouldy/rot. I think you're right about sealing it being a bit of a waste of effort. Ta
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Re: Sealing and waterproofing knots

Postby oldclaypaws » Wed Oct 08, 2014 9:41 am

I built a logstore for my back garden. It was free. Looks nice and well made, with felt for the roof and when it monsooned the other day, hey presto no leaks. I like covering the roof with felt because I want my logs dry.

The logs are on pallets and theres some airflow through the side as they are fence panels. The logs were already dry and well seasoned when they went in. It holds about 12 cu metres of timber, enough to last us a couple of years. The horizontal slats across the front of the logs are just to stop the logs tumbling out, they are removable as each of the three parallel heaps goes down. The idea is to use the left third first, then the middle, then by the time we use the right hand third the left hand one can be being refilled, so the fuel use is rotated and it all spends about a year under cover before going in the woodburner.

log1.jpg


log2.jpg


log3.jpg
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Re: Sealing and waterproofing knots

Postby Terry » Wed Oct 08, 2014 10:14 am

mmm, Paws, seems quite tightly packed? Do you get enough air circulating in the interior?

I am using pond liner for the roofing - last a lot longer than the felt and is very easy to install and is fairly cheap.

Also wonder why so many wood stores have no eaves? A good over hang will allow more open sides for better ventilation.
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Re: Sealing and waterproofing knots

Postby Wendelspanswick » Wed Oct 08, 2014 10:38 am

smojo wrote:Yes the roof will come off. I have thought about that method too but wondered if it would trap moisture between roof and membrane and cause it to go mouldy/rot. I think you're right about sealing it being a bit of a waste of effort. Ta


You can buy breathable roof membrane, but I imagine for the small size of the roof it would work out expensive for a 25m roll!
Might be better to see if you can get a roll end, pop into a roofing company and see if they have any bits over.
I pulled 3 roll ends out of a builders skip.
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Re: Sealing and waterproofing knots

Postby oldclaypaws » Wed Oct 08, 2014 1:16 pm

mmm, Paws, seems quite tightly packed? Do you get enough air circulating in the interior?


I have been a bit keen, but had loads lying round the wood and wanted to get as much as possible under cover before it degraded. The stuff I packed in was already pretty dry, having been cut into rounds some time ago and having had this years long dry spell in the wood. Its quite well seasoned, a mixture of last winters Hazel, Oak cut 2 years ago and left over scrap timber. May not use it until winter 2015/16 unless this year is Arctic, we have loads more under tarps along the fence boundary, the kiln shed is also full, theres loads up by the house, and more in the wood on the ground. We need to get rid of some, got the stuff coming out of our ears !

To be honest I love chopping logs, its my recreation, and will keep at it until I run out of places to put them. Wouldn't have had so much if my wood had been regularly coppiced, but we have 25 years worth of catching up to do, its really overstood. I do leave quite a bit as dead wood heaps too.

There is adequate air getting into my heap from the sides and below, proof was in the 'test' over the last couple of evenings -it already burns well. The oak is amazing, like coal. A couple of decent chunks will burn for an hour or two and it really pumps out the heat. Its best mixed up with some quicker burning stuff like Hazel.

We've had a few double glazing / energy efficiency salesmen over the last month door knocking, they tend to look deflated and puzzled when you say "you can't help us save money on heating thank you- we don't have any heating bills, we own a wood."
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Re: Sealing and waterproofing knots

Postby smojo » Wed Oct 08, 2014 5:44 pm

Cool logstore Paws. Looks very well organised - are you a Virgo by any chance?

Well I got busy this afternoon. Had a cheapo green plastic tarp from £1 shop so stapled it under the roof. Don't expect it to last very long but it's going to be better than none.
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Re: Sealing and waterproofing knots

Postby Terry » Tue Oct 14, 2014 10:32 pm

Paws, if mostly seasoned before stacking I guess it will probably be OK.
I have had a few bad patches in the past when stacking too tidily and not leaving gaps between.

Love it when the energy efficiency people start telling me how much money we could save. :D
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