Is it permissible to pay a bribe to employees in a cement factory to obtain cement at its original price (7 dinars) instead of buying it from the market at double the price (14 dinars), knowing that not paying it will result in exorbitant costs and may prevent the completion of building the house?

If your friend's purchase at the mentioned price does not infringe upon the right of another, and he cannot access the commodity except by paying a bribe to those mentioned, then there is no objection to that, and the sin falls upon the recipient. However, if paying the bribe will lead to him being prioritized over others who preceded him, then it is not permissible for him to do so, due to the injustice involved and aiding in it.