If it's still in good condition there's no reason you can't reuse it, but after a few years it's probably dirty, smelly, and/or no longer very resilient; it doesn't make much sense to install new carpet over an old, dirty, smelly, worn-out pad.
Carpet is not supposed to be glued to the pad, and I really can't imagine what advantage that would give you.
Gluing splices is the common way to lay pad for carpet.
Usually, unless it is less then a few years old and you are replacing it for color or style reasons. But you will most likely void your warranty on the carpet by not replacing it.
Yes
It depends on where the carpet is installed. You want a thinner pad on high traffic areas. A thicker pad will give a softer, more luxurious feel.
No, the carpet pad moves far to much and your tile will look loose and crooked in a very short amount of time. Also, the carpet pad will not allow the adhesive to bond to it.
$1550 uninstalled with pad, $2025 installed with pad
Generally, no. The carpet pad will have too much bounce causing the engineered hardwood (or even laminate) to break and split. That being said there are some thin felt carpet pads that could work, but I wouldn't recommend it. I'm not sure why you are asking this question. If it's because you had carpet there and you are hoping to reuse your existing carpet pad, that is a big no no. The carpet pad will be uneven which can cause problems and worse than that, it will already be dirty with germs and potentially moisture and you could develop mold and/or odor issues. Also, if your engineered hardwood is over concrete, you want the traditional laminate/hardwood underlayment which also has a moisture barrier. This, of course, is assuming that you are doing a floating floor. If you are nailing or glueing than it's an even firmer no.
A carpet runner can brighten up your home when placed in a strategic location such as a hallway, entry way or stair case. Installing a carpet runner can be simple provided that you have the correct tools and know how. To properly install a carper runner, you will need carpet padding, a razor blade, hammer gun/staple gun, straight edge, ruler, pad tape and for stair installations, an electric staple gun.1.) The first step in installing a carpet runner is to measure the area of the installation and map out the placement of the runner, using your straight edge as a guide. This will help to ensure that the carpet runner will be placed in its desired location.2.) Once the measurements have been completed and the placement has been mapped out, deduct an inch from the length and width of your measurements and use your razor blade to cut the carpet pad to that size.*Note: if you are installing your carpet runner on steps, the pad should only go on the tread of the steps, not the riser. Measure your pad to come out to the edge of the nose and a 1/2 gap should be left at the crotch of the step for stapling.3.) If there are any seams in your cut to size carpet pad, join them with pad tape.4.) Using your hammer gun/staple gun, secure the carpet pad in place, ensuring that the pad stays straight and that there is a half inch gap between the edge of the carpet pad and where the edge of your carpet runner will lay.5.) Roll the carpet runner out on top of your carpet pad, ensuring that it remains straight and centered.**If this is a hallway or entry way application, you are done!6.) If you are installing a carpet runner on stairs, you will now need to staple the carpet runner to the stairs with an electric staple gun. Staple the carpet to the nose and crotch of the stairs, ensuring that the carpet remains tight against the stairs.7.) Enjoy the beauty your new carpet runner has brought to your home!
You should get a thin pad that can provide cushioning when covering your tile floor with a layer of carpet. This is so that the carpet can be placed evenly on top without having the grooves of the tile show through
I found an old cup and I decided to reuse it.