GHwerkz is a painting and waterproofing firm on Yio Chu Kang Road in Hougang, and it does both jobs on the same house. Its services are interior and exterior painting, waterproofing, leak repair and renovation. It offers a free site inspection, and its website lists exterior painting from S$4,588 (as at 2026), with 10% off when waterproofing is done at the same time. Customers say the team is professional, careful and on time, and they praise the waterproofing and the external painting. One customer had a whole house painted inside and out, and says the team were polite, communicated well and handled everything with care. Another recommended the firm to their neighbours and to the interior designer they work with. Roof tiles are also mentioned.