> For the complete documentation index, see [llms.txt](https://orbcity.gitbook.io/orbcity/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://orbcity.gitbook.io/orbcity/building/upgrading-system/tier-up-evolution/restoration-cost.md).

# Restoration cost

$$
Restoration~~Cost=\[Lay\_{n}\* t\_r]~~or~~Restoration~~Staking\_{t\_r}
$$

$$
Lay\_{n}=Lay~~Mining~~per\~Day\[Lev.3]
$$

$$
Restoration\~Cost=\[Lay\_{n}*t\_r]*{\[t\_r*24*60*60]-time ~~from~~destruction\over t\_r*24*60*60}
$$

$$
0\le time~~from~~destruction\le{t\_r*24*60\*60}
$$

**t\_r** stands for time. Building owners can choose to pay **t\_r** amount of $Lay007 mined to restore the destroyed building, or they can wait for restoration staking period(**t\_r** amount of time) to restore it.

$$
t\_r=7\~days
$$

{% hint style="info" %}
The value of **t\_r** may be adjusted by governance.
{% endhint %}

{% hint style="info" %}
**Note: Please note that all figures are subject to change by governance.**
{% endhint %}

{% hint style="danger" %} <mark style="color:red;">**Note: Keep in mind that all tokens and NFTs spent on the upgrade are irrevocable and non-refundable.**</mark>
{% endhint %}