The study focuses on the consolidation tests carried out on samples from the Mount Mayamot quarry near Manila. The samples were consolidated using Conservare OH Stone Strengthener (trade name for Wacker OH in the USA). Samples of the tuff, both treated and untreated were artificially aged by wet-dry cycles alternating with exposure to 100% RH. The results, based on microscopy, IR analysius, water absorption data and mechanical tests, showed that even this relatively short artificial weathering produced significant deterioration for both treated and untreated specimens. Apart from an increase in porosity, the main effect observed in the untreated specimens was the partial leaching of iron ions decreasing the colour of the stone to a depth of 2-mm. In some cases, a surface deposition of amorphous silica was observed. For the case of the treated samples, similar but less severe erosion around pumice and basalt clasts was observed. However, under SEM examination it was seen that the polymerization cracks in the silicate ester were increased by microcracking originating from a single point and attribnuted to stress-cracking. Some flaking of the consolidant was observed and all samples showed the presence of a faint white efflorescence of amorphous silica.