Plastic tub support

We have a plastic bathtub that creaks a lot when we step in it. I did a group search, and several times in the past someone has recommended putting expanding foam underneath to support it (for repairs). What kind of foam should I look for? Is it the same stuff used around doors and windows to fill cracks? I assume that the foam won't bulge the tub as it expands? Thanks! Brian
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

The expanding foam WILL distort, and may even dislodge the tub if you use too much of it. You should inject something that expands very little, or not at all. There may be construction foams that are low-expansion, or you may wish to use concrete with a lightweight aggregate. As long as you're cutting a hole in something to get the foam or aggregate in, inspect for water damage and rot while you're under there.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.