Matryoshka words

Since it's Friday and others are playing games, here's another one to take us into the weekend.

Everyone knows about those Russian nesting dolls (called matryoshka dolls, I believe). A small doll nests inside a larger, which itself is inside a larger doll, and so on.

This game does the same with words. You start with a three-letter word, add a letter to make another word, and so on. Longest word wins. The catch? Each additional letter has to form a legitimate word.

Here's one to start you off:

bur
burr
burro
burrow
burrows

Good luck.

Solution 1:

If you're willing to accept the surname "Barrett", the longest I can find (with a program) is 10 letters, "barretters":

bar
barr: to cry as an elephant, abbreviation of "barrister"
barre: (ballet) A handrail fixed to a wall used for ballet exercises.
barret: A kind of military cap
Barrett: A surname (recall Elizabeth Barrett Browning)
barrette: A clasp or clip for gathering and holding the hair.
barretter: A ballast resistor
barretters: plural form of barretter

Solution 2:

I managed to find only eight.

max
maxi
maxim
maxima
maximal
maximals

Solution 3:

Hopefully not breaking the rules here (inserting and prepending allowed):

I
in
sin
sing
sting
string
staring
starling
starlings

Solution 4:

I have 7:

• pa
• pas
• past
• paste
• pastel and pastels

Solution 5:

Here's what I have:

• Pot
• Pots
• Spots
• Sports
• Sprouts
• Supports

I'm not sure if you're allowed to rearrange letters like I did in Supports, so here's another one:

• Pot
• Port
• Porte
• Porter
• Porters
• Sporters