Hi All: I have a question regarding putting insulation(fiberglass) around a cast iron tub as I install it. My only concern is the possiblilty of condensation under and around the tub over time. It seems the condensation might occur anyway with the difference in temperature between the cast iron and the surrounding air. Any thoughts brothers of the blade?
Discussion Forum
Discussion Forum
Up Next
Video Shorts
Featured Story
The "She Build" initiative is empowering women in Seattle, WA by ensuring they have safe, healthy homes.
Highlights
"I have learned so much thanks to the searchable articles on the FHB website. I can confidently say that I expect to be a life-long subscriber." - M.K.
Replies
Have at it! No reason for condensation to occur there anyway (unless you cool your beer in the tub), and the insulation would probably make it less likely, not more so.
Thanks Dan: For the quote that is.....I am a "reasonable man" for which I will try what thou has sanctioned.
Bill
Is the cost of the insulation going to be offset by the savings in the energy required to heat a little bit of water to add to the tub when the water gets too cool? Are you in the tub for long periods of time daily?
I could see adding more insulation than required by code for a house, which has a large mass and is used day in and day out.
Check out the pictures of the insulation for the Endless Pool I'm putting in. It will always be full of water and heated. So I know I want to keep the pool from heating the ground (infinite heat sink).
Best, Woodnuck
Sorry about not making the first picture smaller.
View Image
What is the insulation in the other pic? An inch and a half?
Edited 4/11/2007 9:33 pm ET by rez
The DOW Square Edge is 2" thick and we put two layers on the bottom. We also filled the cracks with gap & crack insulation. The bottom and sides will have 1' of concrete. The top part of the sides of the pool are metal and will be insulated with 2" RFBI.
The pool will hold 5,700 gals of water at 80+ deg F and that is why it needs to be insulated when comparing it to a 50 gal tub that is maybe used daily. Both a tub (100 - 50) and a inground pool (80 - 50) will have the same Delta T of about 30 deg F.
It takes 114 times the amount of BTUs to raise the temperature of the pool vs. the tub. If the tub is used 30 minutes a day then it takes 48 times more energy to keep the pool at temperature.
It will be kind of tough to compact the dirt behind the insulation on the walls. The RFBI is not a structural form for concrete. We also need to keep from damaging the RFBI when backfilling and compacting.
I hope I'm correct on what I have written, Woodnuck.
I recall a number of years back on here or in an old FHB mag ( I believe it was an FHB mag) there was an article where the guy insulated an outdoor tub.
He had rigged up an insulated cover contraption on a long pole weighted on the end providing easy balance where the lid could be lifted and swung to a side when in use and replaced when not in use.
I'm thinking he had 6inches of foamboard as the whole tub was above ground.
Parolee # 53804
You know, because I don't believe the new plastic tubs will last as long as a good Kolher cast tub I chose the latter. As I'm putting it in, the thought occured to me that all that cast iron would be sucking alot of heat up from the bath water on our cooler N. Carolina winter nights. Then I thinks, why not pack the underneath with fiberglass insulation to minimize the heat loss, then I thinks, better put it up for discussion at breaktime and if there is a glaring oversite on my part one of you brothers of the blade would quickly set me straight. So far, it looks like I should do it. By the way, my wife is coming home tomorrow after three weeks in "the old country" giving me time to rebuild our bathroom.. I had a shower for the first time in three weeks last night and I want to say that we don't give hot showers enough credit !
Part of the beauty of a cast tub is that they hold the heat. I had one yrs. ago and I would fill it a little hotter than normal, wait 5 min. and the tub would suck some heat out and stay nice and warm for more than 1/2 hr. (bad back at the time) Insulating will not hurt, but hardly seems nessasary.