The Swiss company said it now expected full year sales growth of "around 3 percent", when adjusted for currency swings, down from its earlier view of 4 percent it had forecasted in August.
"Compared with the situation when the half-year results were published, the forecasts for the building industry are slightly more cautious after nine months – but remain positive overall," Geberit said.
The results of companies like Geberit are closely watched as signals for the health of the broader construction industry, with its products used in new buildings as well as refurbishment projects.
The company said it was still facing problems finding enough installers in Germany, its biggest market, while Austria, France, and the Benelux countries were seeing slower sales momentum.
It was also more cautious about Italy, citing political uncertainty, while it expected a "downward trend" in Britain as a result of Brexit.
Still, Geberit said it expected an operating cashflow margin of around 28 percent for 2018, a similar level to 2017.
The revised outlook came as the company reported net profit and sales both short of expectations during its third quarter.
Net profit of 145.6 million Swiss francs(113.54 million pounds) missed average forecasts for 160 million francs expected by analysts polled by Reuters..
Earnings before interest, tax, depreciation and amortisation of 213.3 million francs was below forecasts of 229 million francs.
Third quarter sales of 740.7 million francs, was also short of forecasts for 760 million francs.
($1 = 1.0017 Swiss francs)
(Reporting by John Revill, editing by Riham Alkousaa)
By John Revill