Situation: old, old house. Crawl space over dirt, 18″-48″ high. New drain tile behind the house, but the crawl space has historically been damp to wet. No insulation in floor, which is a one-layer 1×4 T&G fir floor in most of the house, tile in one bath, vinyl in another, floating floor in the kitchen. California North Coast, which means wet winters, temps down into the teens but usually more like the 20’s at night, high 20’s and up to sunny 60’s during the day. A sweet, loving wife who is NOT thrilled with a cold house.
Weekend worrier job – not a contractor.
I’d been considering one of the panel insulations (EPS or similar – maybe the pink hard foam stuff whose name I can’t remember) foamed in place, but someone recommended radiant barrier instead (http://www.radiantguard.com/).
The radiant barrier looks easier to install, and also to remove and replace for work (seems like we’re always doing something on the house). It would also provide a vapor barrier separating crawl space from house. But I don’t want to invest time and money in something that’s ineffective.
Opinions and experience appreciated.
Bill Houghton
Replies
I am not the best one here to answer your question but this will at least give you a bump. If you were going to use the radiant stuff I would assume that you would staple it on which would rip if you ever tried to remove it to work on something. If you used a sheet foam you could cut it to very manegble sizes and use only a couple of screws into the joist and it would be easily removable.
Radiant barrier ... hmm could you describe? Sounds like a flexible, thin material. Generally I would very rarely if ever recommend a 'radiant barrier insulation'. Radiant barriers work ... in the laboratory. Why rigid foam? Why not batt insulation? Because of the moisture? Pink board would work. Cut it w/ the table saw pretty accurately. Secure in place w/ lots of techniques (including 'blocks' of plywood at each end). For the floor of the crawl, it would be standard practice to cover w/ 6 mil black poly and overlap the seams and then up the foundation wall. This would help minimize moisture and allow you to use batts if you wanted to go that route. The poly would be generally a good idea anyway. Do you have foundation vents? If not, you should consider operable vents to use during the summer.
As long as you're down there ... seal penetrations through the floor to begin to control air leakage.
I would agree with clewless- radiant barrier does not work in most situations. Have you considered sealing and insulating the crawl walls and turnning it into directly or indirectly conditioned space? At the very least, you do need a vapor barrier over the dirt floor. If you insulate the floor and have high moisture in the crawl, you will get mold.
We're committed now - halfway through the installation. We'll see how it works.HMJ, you commented, "If you insulate the floor and have high moisture in the crawl, you will get mold." Will this be true even if the crawl space is ventilated? It's got some vents now, and I plan to add more.There's a whole range of reasons that plastic on the crawl space "floor" can't happen right now; I'll have to hope the drain tile we added this Spring helps, and that more vents help even more.
Houghton,When you have warm moist air entering a cooler crawlspace, it will condense, leaving enough mositure to potentially cause a problem. Ultimately a sealed insulated crawl is the ideal situation. However, if you have exposed ground with no vapor barrier, keep it vented.
Thanks. On the California North Coast, the wet time of year is winter, so cool moist air is more the issue - coupled with some uncertainty about how much ground water we'll be getting.I'll buy and install more vents.
Sounds much like a problem I have. Older house with hardwood floor,minimum height from ground 600mm,house on brick piers and underfloor space is 'open' to atmosphere. 640metres above sea level...short hot [dry] summers and cool/cold winters,with fair rain [hopefully].
Can see ground thru floor in parts, 1 - 1.5 mm spaces between some floorboards.Have plans to fit masonite or similar to underside of joists to keep out the draft.
Does this sound OK?
robin
Sounds reasonable ... seal cracks/holes/openings, then insulate before you put on masonite. I'd install tyvek, then, too behind anything you install down there. Haven't heard much about using tyvek in a crawl/under house situation ... not sure if it is an issue or if I just haven't paid attention to that detail (until now).
Thanks for your thoughts.
Although I've read of Tyvek in many of the articles in Fhb.,and a very useful item it seems to be,we don't have anything down here quite like it.We use a foil faced tar paper [the best way I can describe it !] generically called "sarking"..a brand name is Sisalcraft, not nearly as effective as Tyvek,I think.
Would you fix this to the masonite foil down?
Not sure of the product. Assuming it is not a vapor retarder ... put the foil up. If it is a vapor retarder ... don't use it in that position/location. You should be able to find something similar to tyvek ... there are several products on the market. Where are you located? Maybe that is why they don't use such a product?
Where am I ? [good question :) ] Live in what is described as The Southern Highlands of New South Wales, 45 Km from our Pacific coast but up approx. 650 metres.At about 35 degrees South Latitude we are becoming sub-tropical,but our altitude gives us specific seasons and all the botanical beauty that goes with them.More importantly,we miss the coastal humidity of the mid to late summer,and only have a short period [ a week or two ] of strong heat, 30 - 40 C but without much humidity.
As mentioned ,the crawl-space is completely open to atmosphere,the land is gently sloped therefore well drained and I don't anticipate that water vapour will be a problem. Certainly, the material I've mentioned is no vapour barrier,intended only as a water barrier behind siding and roof tiling,etc. Its foil facing is an attempt at providing a measure of reflectant insulation.By observation,there must be better materials around for THAT job!
Have finaly located the local DuPont agency,and will call them next week to find availability,etc,of Tyvek & tapes.
You suggested insulating the under side of the floor before masoniting.What material would you recommend?
Robin
Not familiar w/ that location ... but it sounds not much different than the inland Northwest here in the states. Somewhat arrid w/ some periods of moisture and drier hot summers. We get on the order of 17-34 inches of rain a year (Seattle more, Spokane less).
So ... I'm thinking fiberglass batts would be fine under your masonite. The tyvek would be to help create a bit of an air barrier. Is your water main protected from freezing? I assume somewhere it goes between the ground and up through the floor.
Fortunately our pipe-freezing time is fairly short,but that said of course,you only need once,do you not? But yes,the pipes are protected,but I plan to re-do the insulation before next winter,[July,August & Sept].
Have tried 3 times this week to speak with somebody from DuPont local office,but haven't had a call back yet...Hate talking to machines.
Yep,I agree,batts would seem the way to go.
Assuming I hear from DuPont at some time shortly,I guess it goes....Batts,board then Tyvek,butt joints tape sealed?
Not sure if I got you right ... batts, board, THEN tyvek? the tyvek goes under the board against the insulation ... you don't normally want to leave tyvek exposed.
You could staple up twine to keep the batts in place until you figured out the tyvek thing if you wanted ... just do a zig/zap pattern. ... but you would normally install the batts up against the floor sheathing ... not sure if you mentioned that. Some codes actually require that, I think (helps prevent moisture problems if I recall).
Remember insulation alone won't prevent a pipe from freezing ... it simply delays the freeze longer so if your cold spells are short, you are probably OK. A trickle of water can ensure safety if it seems to stay cold for long. With global warming .... you might be safe :)
Thanks for the clarification re the Tyvek. Not being able to speak with anyone yet,I'm in the dark with that stuff till I can learn something about it.
You were right,I did have it arse about face! SO,batts,then Tyvek,then board.
Sounds good.
NOW, all I need is for DuPont to get off its collective dot and sell me the stuff!
I'll keep you posted. :)
Don't fall off waiting (the bottom of the earth, that is).
Why is the southern hemisphere considered 'the bottom' or 'down' ? Why are globes always shown w/ the North pole up and all the text written in that orientation. What's up w/ that? I guess the northern hemisphere 'invented' the globe ... they did whatever they wanted. Arrogant aren't we?
Summer's coming ... I know that 'cause I keep track of the sun and it will visit you soon! Hats off, dude. Enjoy whatever you enjoy doing.
Yes,a funny thing that top,bottom business,isn't it?
Apart from the fact that every night [cloudless,that is] I look heavenwards,the constellations are upside down,so I suppose so must we be.
The other thing the answer to which I am still seeking is, [as a wine-o of many summers' standing,also upside down],if France and its neighbours comprise 'The Old World',where does IT end,and you & us, South America & South Africa -- The New World' begin !?
Probably to do with that big dividing meridian separating east / west somewhere.
Time for another glass of red, perhaps...
Actually,just finished reading an article in FHB dealing with mould [sorry,mold] which got me thinking,dangerous,I know, about my soon to be shellac-ed kitchen floor.Kitchens being the way they are,or can be... damp/wet,puddly sometimes,should the underside of the floorboards be treated other than you have suggested?....like left exposed,or sumpn.
Definitely time for a red before I have anymore brain explosions!
What ... you stand'n on your head? REALLY are the constellations upside down down there??!!
Hey ... not sure I understand your kitchen floor question. Maybe we should review the materials in your floor. You got shellac, then wood ... flooring? over subfloor of sorts? then joists and ... lets see ... must be American soil (the deepest part :) ). How am I doing here?
Normally, you want a vapor retarder (we quit calling them 'barriers') on the warm side assuming you aren't a sooper humid tropical type climate. A subfloor usually constitutes a vapor retarder .... at least the plywood type we normally use. If you have floor moisture problems/issues ... vapor transmission is probably the least of your worries ... you'll have floor buckling. Normally it is not OK to leave wetness on your kitchen floors regardless of your finish ... so given that, your kitchen shouldn't be a particular problem, I am thinking. A wood floor takes a little different care than maybe some other resilient floors (e.g. vinyl, or tile).
Thinking more .... eww .... A floor is probably generally not high on the vapor transmission concern list as air leakage will almost always be from the floor up (i.e. in at low levels and out at high levels). Maybe someone esle can comment.
When you drink ... is it bottoms up or do you have to do tops down? :) Confusing ... don't you spill often? I do, but it ain't 'cause I'm upside down. I don't have an excuse.
Sorry, I have confused you by sort of combining 2 threads and leaping from one to the other...probably the red again!
If you can be bothered,the shellac floor finish thing is under a floor finishing/gouge repair thread with "frenchy".Once I finish this note,I'll get the thread number for you.
Simply put [I hope], I'm about to re-do the floors throughout the house,and I was following that thread between frenchy and another person,when frenchy made a silly offer....he'd describe the shellac versus polyurethane thing and how to do it if required.
Puting down me red,I said I would like to know what to do,although I don't have gouges,the floor is pretty tatty and needs refinishing..INCLUDING the kitchen,all hardwood boards.
Then back to our discussion,it just seemed to me that because of the risk of occaisional spills,dishwashers and sinks overflowing,people dropping wine,etc.,etc., coupled with the unlikely 100% waterproofness of my floor,it might be unwise to box in the area under the kitchen with batts,membrane and board.
If you see what I mean.
Incidentally, I didn't answer your question. No,there is no sub-flooring of any sort.Just the floorboards to joists,then space to the ground.[the bottom of the US of A type dirt.]
The thread refered to started life at 110488.1 Frenchy entered at --- .8 then me at----.17
Edited 10/12/2008 9:56 pm ET by pharmachippie
Um ... thanks. I'm thinkin still my comments stand as is. If you have that much water on the floor, you likely have other more important issues. But ... to cover instances where the condition is severe and to cover instances where you might need to access under floor ... e.g. water or sewer piping or electrical or gas under the kitchen ... you could isolate your crawl finish ... masonite ... have the area under the kitchen attached w/ e.g. screws to enable easy future maintenance, repairs, etc. You just pop it off ... dry out if necessary ... replace whatever insulation needs it and you're back up and running.
You've pointed out probably one of the disadvantages of insulating the floor vs. enclosing and insulating the perimeter of a crawl. Generally, better to couple w/ the ground (it's often less area to insulate, too. Can't remember if it was discussed why you were doing the floor vs. the perimeter (yeah, too lazy to blaze through 20 lousy messages :) ).
I take your point.
Was being a bit flippant about the volume of spilt fluid. My only concern was that of small "missed" spills accessing th u/floor area and becoming a starting point for mold growth over time. One would hope that the pre finish sealing will be good enough to stop even small amounts of moisture getting through.
For reasons I can't explain,I looked at your profile only the other day and discovered the source of an unexplained rapport! Although I've never tried my hand at sailboarding,I've been a yachty since short pants days.[Now a LONG time ago!]. Nothing like a blast of fresh air with salt in it to focus one's attention!
About the crawl space,the reason it's not enclosed is that the house is on a sloping site, and is all above ground.I guess them that built it didn't feel the necessity to do footings,only piers!
Thanks again for your far from Clewless input.
Robin
About
clew less ... not clue less being a sailing dude ... you might know the dif. When on break time ... I'm clew less (without clew). Wish I was sailboarding right now. See ya. Good luck.
Yep,you got me on that one. I thought it was some sort of mild self criticsism until I saw your profile,then I was a bit lost.
Good one.
Cheers
Now ... you're a bit more enlightened!! Hey have a good one ... good luck.
clew less .
Seeing that handle always makes me try to recollect a sail wha hae nae clewes.
Only thing that leaps to mind is the triangular form of the spritsail, which only has a tack, and no clew at all. Muttonchop topsail technically has no clew, but the bottom leading edge "corner" lacks any other conventional name, even when permanently rigged to the topmast with rings or a track.Occupational hazard of my occupation not being around (sorry Bubba)
flying over my head, dude. I'm a novice compared to you ... don't have a clue!
flying over my head
Well, I certainly hope a topsail, and the topmast, so associated are over your head, other wise, either your ship has capised (bad), or you are flying trhough the air above the topmast (also generally bad).
now, given that windsurfers are generally rigged over their spars, conventional terminology runs a bit caterwhumpus. I'd likely think of the outboard end the tack, the upper end the head, and the base the clew, out of habit (and from being around Laser sailers, another group of folk given to wetsuits and a milimalist set of rigging).
In my case, being son of a son of a son of a son of a sailor helps (even before Jimmy penned the words <g>). Some of my very first memories of anything at all are of sailing in San Diego Harbor (waving at the submariners, even).Occupational hazard of my occupation not being around (sorry Bubba)
"waving at the submariners.."
Didn't realise it at the time,but when I got onto something with a fixed keel and finished the day almost dry,I was glad my semi-submariner days were over!
Now, i'd probably drown.
Some feedback: the radiant barrier does seem to increase the speed at which the house warms up (we let it drop down into the 50's at night, then start bringing it up to mid-60's about 4 am). I'm not sure there's been a measurable savings on the gas bill, though. Hard to do, considering how wildly variable our winters are - from sub-freezing (even down into the teens) one day to 70s the next, with no pattern from year to year.
It was not too bad a project - the most time consuming part was working around all the bits that hung below the joists - DWV bracing, plumbing pipe, etc.
We are still weighing radiant floor heat, in which case, of course, I'd be doing proper insulation; but this makes LOML happier, and is thus well worth the money and time.