嵩 — be aggravated, grow worse, grow bulky, swell

箱はこのまま持もってくると嵩張かさばるから、袋ふくろに入いれ替かえて持もってきたんだ。

The box was too big and awkward, so I put these in a bag and brought them.

布団は嵩張るので、客布団など使用頻度の低い布団は、圧縮袋に入れて圧縮して保管するのもいいでしょう。

Since futons are bulky, it's a good idea to compress and store futons that are used infrequently, such as guest futons, in a vacuum-sealed storage bag.

消しゴム１にプラスチック等の消しゴムの機能をもたないもの、例えばプラスチック２を、消しゴム器の嵩、容積を増すため、付け加える。

An article having no function of the eraser such as a plastic, for example the plastic 2, is added to the eraser 1 in order to increase the bulkiness and the volume of the eraser.