(ShareCast News) - Housebuilder Berkeley Group looks set to replace industrial engineer Weir in the FTSE 100 later this month when the quarterly reshuffle is announced on Wednesday, according to indicative data from FTSE International which is based on Friday's closing prices.Weir has been included in London's top-flight index for the last five years but its shares have tumbled 48% in the last 12 months amid declining oil prices.Berkeley, however, has gained 37% over the same time period and will join fellow housebuilders Barratt Developments and Taylor Wimpey, which were bumped up to the FTSE 100 at the end of last year as the sector benefited from UK government initiatives to boost the industry.In June, Weir posted a 75% drop in first-half pre-tax profit on the back of a downturn in US oil and gas activity. It said its businesses in oil and gas were affected as oil prices remained around 50% lower than the previous year. This led to significant reductions in activity, with upstream operations in particular impacted.The changes to the index will be based on Tuesday's closing share prices and will come into effect from close of business on 18 September.At 1230 BST, Berkeley shares were down 2.3% at 3,294p while Weir shares were 2.4% lower at 1,370p.