Snow Damage Repair

[Ray]

For an unexplained reason a combination of the easterly wind and the snow seems to have caused some damage to the bottom of wooden liner of one of the side hatch doors of our (self fitout) Reeves narrowboat.

 

The liner is 18mm thick Ash veneered blockboard and the damage means that the bottom 120mm of the liner needs to be replaced. I still have a few pieces of blockboard left from the fit-out but the only suitable piece that I can realistically use appears to be about 1mm thicker than that used for the liner originally.

 

I believe that the recess in the hatch door into which the liner fits such that the front face of the liner is flush with the rounder edge of the door, is only 18mm deep (I'm not near the boat for another week or so to check) which will force the lower part of the liner to protrude. I can't plane the front face of the liner or the veneer will disappear. However doing so on the back side of the liner is an option save that I've heard it said that if one side of a piece of wood is veneered the other side should also be veneered. Taking about 1mm off the back would remove the veneer from that side.

 

The piece of blockboard being added to the liner has been in my garage for about 3 years.

 

The liner is held in place by screws through the edges of the door. It will have several coats of varnish all over before it is refitted.

 

What are the risks of removing the (veneer and) extra 1mm off of the repaired part of the liner, an area of about 120mm deep by 400mm wide?

[Phil Ambrose]

I would avoid Blockboard, try marine ply.

 

Phil

[Ray]

Phil

 

The exisitng liner and the matching one are both veneered blockboard as are all the bulkheads and other door liners. None have given any trouble before and it is not the blockboard itself that has failed, the water has got between the varnish and the under side of the veneer. I would have to replace both liners (and buy at least a full sheet to do so and I was unable to obtain 18mm thick veneered plywood when I last enquired.

 

Edited to correct spelling

Edited April 24, 2013 by Ray

[John Holden]

Phil

 

The exisitng liner and the matching one are both veneered blockboard as are all the bulkheads and other door liners. None have gievn any trouble before and it is not the blockboard itself that has failed, the water has got between the varnish and the under side of the veneer. I would have to replace both liners (and buy at least a full sheet to do so and I was unable to obtain 18mm thick veneered plywood when I last enquired.

 

Get the block board re-veneered.

[Ray]

Get the block board re-veneered.

 

John, do you mean the front face or the rear?

[John Holden]

John, do you mean the front face or the rear?

 

Which ever side has the damaged veneer, unless the back is a better match than new veneer would be, in which case turn it round so that the back becomes the front.

I'm a bit out of touch with prices these days but a re-veneer should cost considerably less than a sheet of block board.

[Ray]

John

 

The the original blockboard liner was veneered on both sides and the discolouration has affected one side worse than the other but both are affected. The liner canot be reversed because there are recessed holes in the back face to accommodate the nuts that hold the door bolts in place.

 

My quandry is that the piece of blockboard that I originally used - bought in good faith as (the metric equivalent of) ¾ inch thick blockboard - fitted the door perfectly. However, other pieces of blockboard also bought in good faith a little later as once again (the metric equivalent of) ¾ inch thick blockboard were not necessarily the same thickness and there is no guarantee that buying a further sheet now (even if I were to consider doing that) would be the same thickness as the original.

 

I can thickness the thicker piece of blockboard - that I would like to use to patch the liner - to the same thickness as the original but that will remove the veneer on the back. My question is "Will removal of the veneer on the rear face of a small part of the liner materially affect the liner given that it will have several coats of varnish applied to seal it and will also be screwd into the door "frame" so, theoretically at least it can't distort too much?"

[Old Son]

I would say that provided it is properly sealed on all faces then you should be OK. I might consider putting some bitumen paint on the back to make sure it is sealed but I'm no expert.

[Bod]

Get enough veneer to cover the back of the new bit.

Thickness down the new bit from the back, equal to the depth required + thickness of new veneer.

Glue new veneer in place.

Replace old damaged bit with new.

 

Stability of blockboard maintained, with new non matching veneer.

 

Do what is required to prevent the fault happening again.

 

Bod

[Ray]

I'm not sure how the damage arose and can but assume that it was driven snow. The metal door shows some sign of light rusting over the metal primer behind the liner but that may have been there when I fitted the liner a few years ago. The liner had several coats of varnish all over (including edges) prior to fitment. The adjacent door liner has not been affected.

 

Somehow the varnish on the liner has managed to go all flaky - I'm sure it wasn't like that at the end of last year. Whether this let the snow in and stain the wood or not I don't know.

 

The weather (and our limited cruising) over the last eighteen or so months hasn't been conducive to having the side doors open for more than a few minutes if I needed to talk to someone outside the boat so I can't think of how the damage has arisen - the hatch is covered on the inside of the boat so I don't think it is condensation from inside either.

[Mike Jordan]

Hi Ray

The thickness of veneered block board has varied over the last few years depending on the original source. I have used some at 18mm and the current lot is about 19.6mm, this can be an expensive problem for me since i use a machined edging/fiddle rail in solid timber which needs to be a spot on fit over the board edge!

Water soaking up into the bottom of side door linings is a very common problem, its sometimes made worse by the bottom of the steel doors being made with a sloping bottom edge which traps water blown in by high winds. If this is the case a couple of holes drilled through the steel under the outside edge may improve matters. Alternatively you can edge round the block board with solid timber lippings which won't absorb the water so readily, or better still, use a solid edging on the bottom edge only and leave a gap of about 5mm between the bottom of the liner and the steel door. The suggested gap is normally covered by the frame when the doors are closed so it won't look unsightly.

You are right about veneering both faces of boards to keep them flat but a don't think this will be a problem in this case.

Mike

Edited April 26, 2013 by Mike Jordan

[Ray]

Mike

 

Thanks for the ideas/suggestions.

 

The fold in the metalwork at the bottom of the door looks almost at 90º, unlike the top where it seems nearer to 45º.

 

The doors generally sit snug against the metal frame of the hatch opening in the side of the boat so there's no realistic option for leaving a gap between door and frame - there's enough draft coming in from the gap between the two doors as it is.

 

I think my only soultion is to do as you say and drill a small hole in the bottom fold of the door and hope this allows any water to drain out. T'is strange though that the damage is only on the front face of the wooden liner which suggests that the water somehow managed to run down the inside face of the door and congregate in such a way that it seems to have eventually managed to break the varnish down and soak into the veneer.

[BEngo]

Mike

 

T<SNIP>

 

T'is strange though that the damage is only on the front face of the wooden liner which suggests that the water somehow managed to run down the inside face of the door and congregate in such a way that it seems to have eventually managed to break the varnish down and soak into the veneer.

Perhaps there has been condensation on the inside face? With snow plastered all over the outside face of the door keeping it cold but a bright sun shining in through the windows there would be a cold surface in a warm space. A perfick recipe for condensation.

 

N

[Ray]

Perhaps there has been condensation on the inside face? With snow plastered all over the outside face of the door keeping it cold but a bright sun shining in through the windows there would be a cold surface in a warm space. A perfick recipe for condensation.

 

N

 

Thanks for the suggestion.

 

Alas, all the drop back vents were left open throughout the winter and all the curtains were drawn closed. The door alongside the affected one was unscathed and both are behind a perspec screen that whilst not air tight, means that the air airflow across the doors was from the gap between the two doors, behind the screen. In addition, during the winter the sun never sees that part of our boat (on either side) because of a railway embankment on one side and buildings on the other.