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Post by bromleyxphil on Nov 8, 2016 8:14:15 GMT
Why does no one seem to insulate under the floor on a narrowboat, yet I read lots about older boats rusting from the inside under the floor. When I ask, and I do, the only answer I get is "it's for ventilation". I know you have to have ballast down there but surely that can be worked out and incorporated into the steel floor at build. If the floor was then grit blasted, two pack painted and then spray foamed flush to the spars, surely there would be no need for said ventilation and the rust couldn't get in. Sorry if you are sick of educating folk like me but I can't look at something and not question if I see another solution.
Phil
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Post by Delta9 on Nov 8, 2016 8:32:52 GMT
If you get a leak in the water system you won't want a bilge full of insulation.
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Post by tonyqj on Nov 8, 2016 8:57:54 GMT
The other consideration is internal headroom. Sure you could have the base plate then ballast then (removable) insulation then battens, then floor boards but now you've lost an extra 6" internal headroom. You can't have a whole lot more than around 2' 6" draft on today's canals if you don't want to be dragging along the bottom, so if you've got 10" of base plate + ballast + insulation + floor and you want 7' internal headroom your air draft will be too high to fit under low bridges.
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Post by JohnV on Nov 8, 2016 8:59:29 GMT
Sabina H has very deep frames in forward areas (she's not a narrowboat) and has 2 x 4 bearers on top of the steel frames supporting the floor. The areas that are not full of ballast are stuffed with plastic crates ..... all full of things that might come in useful one day (otherwise known as junk) In the fo'csle (a twin bedroom, nominally semicircular in shape at the fore end with 15' diameter but 12' fore and aft) 2" celotex was inserted into the gaps of the 2 x 4 bearers. There is a noticeable difference in the amount of heating needed for this room. This however might not be due entirely to the sub floor insulation as the insulation generally in this cabin is higher standard than elsewhere (last room to be fitted out  ) I have had no issues with condensation in the bilge, the resident spider population seems quite happy. I have decided that as other areas need re-furbishment (some areas were done 16 or 17 years ago) I will be upgrading to the same standards (where possible). As regards to ventilation under the floor ...... there are things called ventilation grills  Standard methods of boat fitting out often have a good practical reason for being done that way ........ but that should not stop you thinking outside the box. Sometimes new materials and techniques come along and that can open up new opportunities for change, Tradition can sometimes block progress. The KISS principle, however, should always be maintained where boats are concerned |
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Post by bodger on Nov 8, 2016 8:59:35 GMT
yeah, just call the space under your floor 'the sump'.
if you want a warm floor then build the insulation into the floor, not the space below.
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Post by bromleyxphil on Nov 8, 2016 9:13:45 GMT
The other consideration is internal headroom. Sure you could have the base plate then ballast then (removable) insulation then battens, then floor boards but now you've lost an extra 6" internal headroom. You can't have a whole lot more than around 2' 6" draft on today's canals if you don't want to be dragging along the bottom, so if you've got 10" of base plate + ballast + insulation + floor and you want 7' internal headroom your air draft will be too high to fit under low bridges. I mean permanent sprayfoam insulation within the current height of the floor spars. A water leak then couldn't get into the bottom of the boat so would leak onto the floor, meaning you might spot it sooner. phil |
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Post by peterboat on Nov 8, 2016 9:42:30 GMT
Plenty of boats have thick baseplates and underfloor insulation. I have seen boats with underfloor heating run from the engine that works really well [they were constant cruisers]. You arnt doing or thinking anything new its just whether it will work for you that matters
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Post by tonyqj on Nov 8, 2016 10:12:49 GMT
The other consideration is internal headroom. Sure you could have the base plate then ballast then (removable) insulation then battens, then floor boards but now you've lost an extra 6" internal headroom. You can't have a whole lot more than around 2' 6" draft on today's canals if you don't want to be dragging along the bottom, so if you've got 10" of base plate + ballast + insulation + floor and you want 7' internal headroom your air draft will be too high to fit under low bridges. I mean permanent sprayfoam insulation within the current height of the floor spars. A water leak then couldn't get into the bottom of the boat so would leak onto the floor, meaning you might spot it sooner. phil Yep, that would work if you didn't need any movable ballast |
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Post by lollygagger on Nov 8, 2016 10:49:21 GMT
Mine has paving slab ballast and a 2" layer of polystyrene insulation on top. The problem is that the heat isn't trying to escape downwards. It's typical of a space with large expanse of single glazed windows, cold feet and brightly glowing ears. I had a summerhouse office that was the same, and so is my camper van. Such is life.
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Post by pǝʇɹǝʌuı on Nov 8, 2016 11:21:25 GMT
I suppose it depends on how you are going to use the boat and to what level of effort and expense you are wiling to go. Is underfloor heating a viable option in a liveaboard narrowboat?
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Post by Jim on Nov 8, 2016 13:03:23 GMT
I laid laminate floor insulation on top of the 19mm ply base, its about 4mm + gold foil space blanket, then laid 19mm oak t&g on top of that, so there's some insulation but it doesn't affect headroom.
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Post by Deleted on Nov 8, 2016 13:04:35 GMT
Not sure about underfloor heating and how practical it would be but I heard it suggested (possibly on another internet forum) that well positioned fans pushing air down from the ceiling can help with s cold floor. Have not tried it so it may well be worthless advice . |
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Post by naughtyfox on Nov 8, 2016 16:54:41 GMT
I wear training shoes inside our boat - a special pair only for inside use. That's insulation enough, surely? Our floor seems to be some kind of cork tiles.
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Post by peterboat on Nov 8, 2016 17:00:54 GMT
I suppose it depends on how you are going to use the boat and to what level of effort and expense you are wiling to go. Is underfloor heating a viable option in a liveaboard narrowboat? In the Narrowboat I met in the depths of winter it was a great option the boat really was warm! It ran from the engine they had a stove as well but didnt seem to need it on days they were cruising. If I was building my boat from scratch I would install it I think along with a 20 mm baseplate to keep the boat down in the water!! |
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Post by Deleted on Nov 8, 2016 17:11:06 GMT
That sounds like a goof system. Not sure about 20mm base though isn't that a bit heavy for the welds? Plating and welding is another topic - sorry!
My barge has a 15mm base with 8mm chines - this does give good headroom in the cabin and low air draft as well as relatively shallow water draft.
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