I was going to link to this article but I could neither find nor remember where I found it, so I am copy/pasting it instead:
Weights for a Few Unusual Items
The equipment tables in the Player's Handbook don't quite cover everything a character might decide to pick up and carry. Here are weight figures for a few such items.
Item Weight
Armchair 20 lb.
Chair, simple 5 lb.
Door, iron 3,200 lb.
Door, stone 2,200 lb.
Door, simple wooden 150 lb.
Door, good wooden 225 lb.
Door, strong wooden 350 lb.
Footstool 2 lb.
Petrified creature x8 lb.
Spirits, cask 18 lb.
Spirits, hogshead 750 lb.
Spirits, keg 90 lb.
Spirits, barrel 375 lb.
Statue, Colossal metal 1,750 tons
Statue, Colossal stone 1,250 tons
Statue, Gargantuan metal 875 tons
Statue, Gargantuan stone 625 tons
Statue, Huge metal 112 tons
Statue, Huge stone 80 tons
Statue, Large metal 14 tons
Statue, Large stone 10 tons
Statue, Medium metal 3,500 lb.
Statue, Medium stone 2,500 lb.
Statue, Small metal 420 lb.
Statue, Small stone 300 lb.
Table, banquet 225 lb.
Table, small 60 lb.
Tapestry 100 lb.
Workbench 300 lb.
Table Notes
Here are a few notes to clarify the table entries.
Armchair: This entry assumes fine hardwood construction and a leather or cloth cover. The weight given is for a chair built for a Medium creature. Cut the weight in half for each size category below Medium and double the weight for each size category above Medium.
Chair, Simple: This is a plain chair made from inexpensive hardwood, and it has no arms. See the armchair entry to adjust the weight for larger or smaller creatures.
Doors: All doors are assumed to be 8 feet high and 5 feet wide, with thickness as noted on Table 3-10 in the Dungeon Master's Guide. The listed weight includes hinges, handle, and lock appropriate for the door's overall construction.
Footstool: This assumes a plain, wooden stool about 6 inches high, with a round top about 18 inches across.
Petrified Creature: To calculate a petrified creature's weight, multiply the creature's normal weight by 8 and add the weight of any gear the creature was carrying at the time of petrification. When a creature is magically turned to stone, it and all its gear turn to stone. This tends to make metal gear weigh a little less, but nonmetal gear gets heavier, so the two tend to average out.
Table, Banquet: This table is built to comfortably seat twelve Medium creatures (about 4-1/2 feet wide and 8 feet long). See the armchair entry to adjust the weight for a table built to seat larger or smaller creatures.
Table, Small: The represents a plain wooden table that might be found in a modest home or merchant's shop. It's big enough to seat six Medium creatures (about 3-1/2 feet wide and 7 feet long). See the armchair entry to adjust the weight for a table built to seat larger or smaller creatures.
Spirits: The spirits entry assumes a barrel-shaped container made from hardwood staves and iron hoops. A cask contains 2 gallons of liquid, a hogshead holds 88 gallons, a keg holds 10 gallons, and a barrel holds 44 gallons. You can use these figures for any liquid-based contents. Containers with dry contents might weigh anywhere from one quarter to two-thirds as much.
Statues: Metal statues assume hollow construction from bronze or wrought iron. Stone statues are solid marble. Statue sizes refer to creature sizes from Table 7-1 in the Monster Manual, and they represent figures in the mid range for each size category. A statue of the listed size could easily weigh anywhere from one half to twice the listed weight. All statue weights include an attached base or pedestal.
Tapestry: Assumes a woven wool tapestry about 10 feet square and about 1/4 inch thick. You also can use this figure for carpets or rugs.
Workbench: This is a bench about 3 feet high, 3 feet wide, and 8 feet long, with sturdy legs and top and a shelf or footrest below.
I hope this helps.
Ciao
Dave