To apply a new waterproofing membrane on top of an old bitumen waterproofing membrane, the surface of the old membrane should be thoroughly cleaned and prepared. Any loose debris, dirt, or old adhesive should be removed to ensure proper adhesion of the new membrane. Once the surface is clean, a primer should be applied to promote adhesion between the old and new membranes. Finally, the new waterproofing membrane can be installed according to the manufacturer's instructions, ensuring that it is properly sealed and bonded to the old membrane to provide effective waterproofing. **

A utility knife or a sharp blade is typically used to cut the waterproofing membrane. It is important to use a sharp tool to ensure clean and precise cuts, which will help in achieving a proper seal and prevent water leakage. Care should be taken to avoid damaging the underlying surface while cutting the membrane. **

Ideally, the waterproofing membrane should be applied in dry weather to ensure proper adhesion and effectiveness. If the membrane is applied and then it rains before it has fully cured, it can compromise its ability to create a watertight seal. Water exposure during the curing process can lead to delamination, reduced adhesion, and potential leaks. Therefore, it is best to apply the waterproofing membrane when there is no rain in the forecast and allow it to fully cure before any water exposure. **

Leather shoes can become cracked after waterproofing because the process of waterproofing can sometimes dry out the natural oils in the leather, making it more prone to cracking. Additionally, some waterproofing products contain chemicals that can be harsh on the leather, leading to damage and cracking over time. It is important to use a high-quality leather conditioner in addition to waterproofing to keep the leather supple and prevent cracking. **

Leather shoes darken after waterproofing because the waterproofing product penetrates the leather and changes its appearance. The product creates a protective barrier on the surface of the leather, which can alter its color and texture. Additionally, the process of applying the waterproofing product can also cause the leather to darken as it absorbs the product. This is a natural reaction and should be expected when waterproofing leather shoes. **

If shoes have blue stains after waterproofing them, it is possible that the waterproofing product used contained a dye or colorant that transferred onto the shoes. To address this issue, it is important to carefully read the instructions on the waterproofing product and ensure that it is suitable for the material of the shoes. If the stains persist, it may be necessary to try a different waterproofing product or seek professional help to remove the stains. **

If shoes have blue stains after waterproofing, it is possible that the waterproofing product used contained a dye that transferred onto the shoes. To address this issue, you can try gently wiping the stained areas with a damp cloth to see if the stains can be removed. If the stains persist, it may be necessary to seek professional help or use a stain remover specifically designed for the type of material your shoes are made of. It is also a good idea to carefully read the instructions on the waterproofing product before using it to prevent similar issues in the future. **

Shoes typically need to stand for at least 24 hours after waterproofing to ensure that the product has fully dried and bonded to the material. This waiting period allows the waterproofing agent to penetrate the fabric or leather and create a protective barrier against moisture. It is important to follow the manufacturer's instructions for the specific waterproofing product being used to achieve the best results. **